Download Sample Exam 2 - Gardening Solutions

Sample Exam 2
Master Gardener Reference Questions and Answers
NEMATODES
T or F
1. The presence of nematodes is always evidenced by knots or galls on the plant roots.
T or F
2. Thinning out of lawn grass and the encroachment of weeds often indicates a nematode
problem.
T or F
3. There are several effective nematicides which can be purchased off-the-shelf for use on
lawns and ornamentals.
T or F
4. Most above ground symptoms associated with nematodes may also be caused by other
sources of root stress, such as fungal pathogens, soil compaction and inadequate water.
PLANT PATHOLOGY
T or F
5. The major pathogens which cause plant diseases are bacteria, fungi, and viruses.
T or F
6. Disease develops only when three "ingredients" are present: a susceptible plant; an
aggressive, infectious organism; and a favorable environment.
T or F
7. The occurrence of virus diseases is favored by dew, rain, fog or late night watering.
T or F
8. Fungicides should be more appropriately named "fungistats" since they suppress fungus
growth for the application interval on the product label.
T or F
9. Varieties of vegetables exist with tolerance or resistance to particular plant diseases.
T or F
10.Plants with disease resistance do not become diseased by any pathogen.
T or F
11.Tolerant plants to specific diseases still become diseased, as do susceptible plants, but can
still yield favorably.
T or F
12.Some diseases can be seedborne or transplant-borne.
ENTOMOLOGY
T or F
13.Insect mouthparts are classified into three general types: chewing, piercing-sucking, and
siphoning.
T or F
14.The life cycles of beetles and butterflies are referred to as a complete metamorphosis.
T or F
15.Ants can be distinguished from termites by the strong constriction or "waist" between the
thorax and abdomen of the ant and by the presence of two pairs of wings that are
approximately equal size on ants.
Soils and pH
1. What is pH?
2. What is the best soil pH?
3. Why is pH so important?
4. When should soils be limed?
5. How does dolomite differ from lime?
6. What will a standard soil test tell me?
7. How do I take a soil sample correctly?
8. What is the best type fertilizer to use?
9. What does 100% organic mean?
10. My soil is too alkaline (basic). How can I lower the pH?
.
Landscape Horticulture - Shrubs and Trees
1. My azalea leaves are turning yellow - what is the problem?
2. Should I mulch the soil around my plants?
3. When is the best time to transplant my plants?
4. How deep should I plant my trees and shrubs?
5. When should I prune my plants; is there a general rule?
6. If I wet down my plants before a freeze, will this protect them?
7. Every fall the older leaves on my gardenia and hibiscus shrubs turn yellow and drop, what could cause
this?
8. Why didn't my poinsettia bloom by Christmas?
9. The flower buds on my hibiscus and gardenia plant drop before they open; what could cause the
problem?
10. My camellia leaves have yellow markings on the upper leaf surface and under the leaf is all white. Is
this an insect or disease?
11. My poinsettia is showing spots on the foliage and creamy colored scab-like lesions on the stem. What is
this and how can I get rid of it?
12. My roses have black spots with irregular edges on the leaves. Some spots have yellow rings around
them. The leaves are even dropping now. How do I treat this?
13. The trunk of my oak tree is covered with a silky web and there are little tiny insects under this web.
How do I get rid of these before they kill my tree?
14. My oleander is covered with reddish-orange colored worms with black hairs. They are stripping my
plant of its foliage. What should I do?
15. It looks like something is pruning the twigs on my oak, dogwood, or maple tree. Every day I find more
twigs under the tree and they have all been cleanly cut. What is doing this?
16. My crape myrtle has a powdery-like substance on the leaf surface. The leaves then curl up and die. Is
this a fungus?
17. The bark on my Chinese elm is splitting and peeling off, and it is orange where the bark has come off.
Is this a disease?
18. This year my azaleas and sycamore leaves got a bleached-out appearance and the underside of the
leaves was covered with black tar-like spots. What causes this?
19. I have a stand of pines on my property. One after another is turning brown and is dead within two
weeks. There is some sawdust at the base of the tree and sap on the trunk. Can I save my trees?
Fruit Crops
1. Why doesn't my apple tree set fruit?
2. What pecan variety can I grow here?
3. What plum variety can I grow here?
4. Every year I get little worms in my peaches, pears, guavas, and papayas. What are they and can
anything be done?
5. Why aren't my blueberries growing well?
6. How do I fertilize citrus?
7. Why are citrus fruits splitting? What can I do about it?
8. I get lots of citrus bloom but relatively few fruit, what is the problem?
9. Should I mulch citrus?
10. The leaves on my fig tree turn spotty brown and drop. What is the problem?
Environmental Horticulture - Houseplants
1. My weeping fig tree in my living room was beautiful and full, but now it is dropping all of its leaves.
What is the problem?
.
2. I can never get interior palms to do well in my home. Are they hard to grow?
3. My fern have small white scales. What can I spray them with?
4. My African violets look very healthy but they don't bloom. What could the problem be?
5. The tips of my spider plant leaves turn brown and shriveled. What causes this?
6. What is good potting media for my houseplants?
7. My petunias are wilting and collapsing even though I have watered adequately. What is the problem?
8. My ferns have brown spots on the underside of the foliage. Is this an insect or disease?
9. How do I get my Christmas cactus to bloom?
10. Why do the buds on my Christmas cactus drop?
Vegetable Crops
1. My squash fruits get about 3-4" long, then shrivel up and die, what is the problem?
2. What causes hard white or colorless spots around the outside of my tomatoes?
3. Why do my tomato plants consistently drop their blooms?
4. After my seeds germinate and start growing the little seedling just turns brown and collapses at the soil
level. What is the problem and how can I treat it?
5. My okra and other vegetables were not growing well and when I pulled them up, the roots were covered
with tumor-like growths? What is this?
6. When I plant my onions all I get are green onions - they never bulb - why is this?
7. The bottom of my tomatoes has dark brown, rotten spots. What is this and how can I prevent this
problem?
8. I understand that if I plant different cucurbits in the same garden area that cross pollination will occur.
Will I get unusual fruit?
9. I planted vegetable seeds, but nothing came up. What happens to them?
10. Can I grow asparagus in Florida?
Environmental Horticulture - Turf grass
1. What is the best fertilizer for my St. Augustine grass lawn? How often should I fertilize it?
2. Every winter my lawn turns brown, but I have noticed some lawns in my neighborhood remain green
all year. What grass is this?
3. How often should I water my grass? And when is the best time of the day to do this?
4. I haven't been able to find St. Augustine grass seed. Do you know where I can get it?
5. What type of grass will grow in my shady lawn?
6. Every spring my Bahiagrass lawn develops yellow spots even though I fertilized, what causes this?
7. When should I reseed my Bahiagrass lawn? I have had trouble getting the seed to grow.
8. I have read about this wonderful miracle grass called Zoysiagrass. Is it as good as the advertisement
says?
9. I can control most of the weeds in my lawn, but I always have difficulty with grassy weeds. Any
suggestions?
10. Should I leave my grass clippings on the lawn or should I have a catch bag on my mower?
Compiled by: Sydney Park Brown, Associate Professor of Environmental Horticulture
ANSWERS TO MASTER GARDENER SAMPLE EXAM 2
1.
F
2.
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3.
F
4.
T
5.
T
6.
T
7.
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8.
T
9.
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10.
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11.
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12.
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13.
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14.
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15.
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Soils and pH
1. What is pH?
pH is a measure of acidity or alkalinity. pH is expressed by a number on a scale from
0-14. A neutral reading is 7. Any reading below 7 represents an acidic condition and
the smaller the number the more acidic the condition. Any number above 7 indicates
an alkaline condition and alkalinity increases as the number on the scale increases.
2. What is the best soil pH?
Optimum soil pH will vary from plant to plant, but considering all factors, a pH
between 5.4 and 6.5 is generally accepted as the best range.
3. Why is pH so important?
The pH of the soil has a direct influence on what nutrients are available to plants. If
the pH is above or below the recommended range for that plant, then nutrients may
not be soluble (absorbable by plants) or they may be so soluble that they leach or
become phytotoxic. Therefore, the plant can show signs of nutrient deficiencies or
toxicity even when the correct amount of fertilizer is applied to that plant. pH also
influences the activity of soil microorganisms. Compost piles depend on the
decompositional activity of bacteria and fungi. Therefore, lime is usually added to
compost piles to keep the pH in a range suitable for maximum bacterial action.
4. When should soils be limed?
Lime is added to the soil when a soil test determines that the soil pH is too acid. It is
the carbonate ion which neutralizes the acid. It results in carbon dioxide and water, if
the reaction goes to completion.
5. How does dolomite differ from lime?
Dolomite is a liming agent or material. There are various forms of lime that are used
to increase soil pH. Standard lime contains mostly calcium carbonate. Dolomitic lime
is a mixture of calcium and magnesium carbonates. Whenever liming is
recommended, dolomite is often suggested since it will adjust the soil pH and also
add magnesium which is often deficient in Florida's sandy soil. (However, the
Extension Soil Testing Lab may recommend either source if magnesium is greater
than 30 ppm extractable.)
6. What will a standard soil test tell me?
A standard soil test conducted at the Extension Office will tell you the pH of your
soil. It will not tell you the fertilizers you need, what diseases are present in the
sample, or any other reasons why plants won't grow in an area. A test for soluble salts
is also available. Excessive soluble salts may indicate salt intrusion in well water or
over fertilization.
7. How do I take a soil sample correctly?
Using a trowel, dig a V-shaped hole in the soil four to six inches deep. Remove a
"slice" from one side of the hole. Collect similar "slices" from several spots in the
area you wish to plant. Mix all the individual "slices" together. One-half pint of this
mixed sample is sufficient for testing purposes. The sample should be free of all plant
debris and rocks, but should include all the "dust" (fine particles).
8. What are the best type fertilizers to use?
A complete fertilizer is best for most plants. A complete fertilizer means that all three
major elements - nitrogen, phosphorous, and potassium - are available in that
fertilizer in some proportion. It is also recommended that a fertilizer containing other
elements such as iron, manganese, sulfur, etc. be applied once a year. These nutrients
are listed on the label as secondary and/or minor plant nutrients. For a "long lasting"
fertilization select a fertilizer containing some percent "Water Insoluble Nitrogen".
9. What does 100% organic mean?
This term causes a lot of confusion. It is used in fertilizer advertisements because
many people incorrectly associate "organic" with "slow release" in the context of
fertilizers. However, this is not necessarily the case. That 100% (all) of the material is
composed of an ingredient that can be found as a natural product of biological
systems.
Nitrogen which is WATER SOLUBLE is readily available to plants but it is also
readily leachable. As such, it can be lost to plants and can contribute to environmental
pollution. Nitrogen which is NOT water soluble requires time in the soil to become
water soluble and is thus considered slow release and less likely to be lost to leaching.
WATER INSOLUBLE nitrogen can come from natural organic materials (e.g. seed
meals, sludge, dried blood, etc.) as well as from certain forms of manufactured
(synthetic) organic materials (e.g. urea-formaldehyde, isobutylidine diurea [IBDU],
etc.). These are the SLOW RELEASE nitrogen fertilizers.
WATER SOLUBLE nitrogen can be either organic(e.g. urea) or inorganic (e.g.
various nitrate and ammonium salts). It can be natural and manufactured.
Florida fertilizer law, in trying to protect the consumer, requires that the various
forms of nitrogen be specified on the fertilizer tag. This gets pretty complicated
because terms like "water soluble organic N and or urea N", "water insoluble N", and
"synthetic organic N" are needed. These terms are not readily understood by many
consumers.
10. My soil is too alkaline (basic). How can I lower the pH?
Alkaline soils are a result of natural soil characteristics or excessive applications of
lime. The pH of over-limed soils can be lowered by adding elemental sulfur.
Naturally alkaline or calcareous soils are common in coastal counties. It is difficult, if
not impossible, to lower the pH of these soils. Nutrient deficiencies in plants growing
on calcareous soils should be treated by nutrient foliar sprays. Plants that are tolerant
of high pH should be used to avoid continuing problems.
Landscape Horticulture - Shrubs and Trees
1. My azalea leaves are turning yellow - what is the problem?
Azaleas are acid lovers. Certain minerals, including iron, are more available at lower
pH values. Yellow leaves on azaleas can indicate an iron deficiency because (1) not
enough iron is present in the soil for the azaleas to utilize, or, more commonly, (2) the
pH is too high to release the iron that is present. Azalea fertilizer is usually a
sufficient acidifier to keep the soil within the proper pH range for maximum nutrient
availability. Supplemental applications of iron in the form of iron sulfate or iron
chelate will supply iron when the azalea fertilizer is inadequate.
It is nearly impossible to permanently adjust a naturally alkaline soil. Therefore,
azaleas and other acid-loving plants should not be selected for that site.
Also remember that mites, poor drainage, low nitrogen, and/or too much sun can also
turn leaves yellow.
2. Should I mulch the soil around my plants?
Mulching is considered a beneficial practice for all ornamental plants except for
bedding plants. Mulching conserves soil moisture and keeps the soil cooler in
summer and warmer in winter.
Organic mulches such as wood shavings, pine bark or leaves are preferred to
inorganic mulches such as pebbles and stone. The desired depth of the mulch is 2-3"
after settling. The area immediately around the stem of the plant should be left free of
mulch.
3. When is the best time to transplant my plants?
Container plants can be planted any time of the year. The critical factor is keeping the
root ball moist for several weeks to several months after planting.
The dormant period of the year is the best time to dig and move plants that are
existing in the landscape. The next best time is just after a growth flush has hardened
off. Plants that are root pruned 6-10 weeks before moving, then dug just beyond the
root-pruned area may survive better than unpruned plants.
4. How deep should I plant my trees and shrubs?
Never transplant ornamental trees and shrubs any deeper than they were already
planted. After digging the planting hole only as deep as the root ball, backfill around
the root ball using existing soil so that the plant will sit in the hole at the same level it
was growing in the container. Research indicates that the addition of organic
amendments is not needed.
5. When should I prune my plants; is there a general rule?
The time for major pruning of ornamental plants depends upon their growth and
blooming habit. It is best to prune in the dormant season or following a growth
(shoot) flush. In general, shrubs and trees which bloom during the winter and spring
should be pruned immediately after flowering ends. Since these shrubs produce next
year's flower buds in early summer, blooms will be sacrificed if pruning is done in
summer or fall. Shrubs which bloom during the summer and fall produce flowers on
the current season's growth. Therefore, the best time for pruning would be in late
winter or very early spring before new growth starts to develop. Pruning at other
times is okay but you'll lose some blooms.
Evergreen shrubs and trees which are grown primarily for their foliage may be pruned
anytime, but major pruning is best saved for late winter. Shrubs and trees which lose
their leaves during the winter months may be pruned as soon as all leaves fall.
6. If I wet down my plants before a freeze, will this protect them?
No. Merely wetting down the foliage so that ice forms on the plant could be more
damaging than doing nothing. Ornamental plants can be protected during a freeze by
continually sprinkling the plants with water. Sprinkling must begin when the
temperatures drop to 32°F and must continue until the temperatures rise above 32°F.
Sprinkling must be such that the water is evenly distributed and ample enough to
maintain a film of liquid water on all of the foliage surfaces. This practice is
impractical and not recommended for homeowners since home irrigation systems are
inadequate for such extensive water delivery. Water pressure may drop if several
homeowners in the same area turn on their systems, making adequate water delivery
impossible. Several hours of irrigation may be necessary and this can cause soil
saturation resulting in root rot. It also wastes large quantities of water.
7. Every fall the older leaves on my gardenia and hibiscus shrubs turn yellow and drop,
what could cause this?
When healthy gardenias and hibiscus are exposed to cool evening temperatures and
warm days, it is not uncommon for some older leaves to turn bright yellow and drop.
There is no treatment or prevention for this since this is normal.
If yellow leaves and leaf drop occur at other times of the year, it is a sign of stress
resulting from water stress, improper fertilization, root disorders, nematodes, or
misuse of chemicals.
8. Why didn't my poinsettia bloom by Christmas?
This could have resulted from a couple of problems. First, poinsettia should not be
pruned after September 10th. Flower buds are set sometime between September 10th
and shortly after October 10th. Pruning anything within this period could remove
those initiated flower buds.
Secondly, flower initiation in poinsettias is stimulated by long nights and any light
interruption during that necessary dark period can delay flowering. Light from a street
light, interior light, or headlights from a passing car is sufficient to interfere with the
flowering process.
9. The flower buds on my hibiscus and gardenia plant drop before they open; what could
cause the problem?
Premature flower bud drop is often a problem with both of these plants and can
indicate an insect problem, cultural/environmental problems, or a varietal
characteristic.
Insects called thrips can damage the unopened bud. These may go undetected until
considerable damage has occurred and the buds drop.
Too much or not enough fertilizer or water can stress the plant - resulting in bud drop.
Nematodes can parasitize the root system, creating a water and nutritional stress on
the plant, also resulting in bud drop.
Some varieties of hibiscus, especially doubles, are characterized by premature bud
drop. Some varieties bloom well during one period of the year and consistently drop
their buds at all other times.
10. My camellia leaves have yellow markings on the upper leaf surface and under the leaf
is all white. Is this an insect or disease?
This is an insect called Tea Scale and it is the worst pest on camellias. It is difficult to
treat with contact insecticide because total coverage with the insecticide on the
underside of the leaves is necessary. Therefore, treating with a systemic insecticide or
horticultural oil is recommended.
11. My poinsettia is showing spots on the foliage and creamy colored scab-like lesions on
the stem. What is this and how can I get rid of it?
This is a disease called poinsettia scab. The diseased tissue must be pruned out. Once
the poinsettia begins to flush out with new growth, spray with appropriate fungicide
and repeat on the next two growth flushes.
12. My roses have black spots with irregular edges on the leaves. Some spots have yellow
rings around them. The leaves are even dropping now. How do I treat this?
Black Spot is the most common foliage disease of roses. The disease can only get
established when the foliage stays wet for 6 hours each day or longer, and is spread
by splashing rain.
Control is accomplished by keeping the foliage dry and spraying weekly with a
recommended fungicide.
13. The trunk of my oak tree is covered with a silky web and there are little tiny insects
under this web. How do I get rid of these before they kill my tree?
These insects are called Psocids. They do not damage trees or ornamentals. They only
feed on the decaying organic matter that is trapped in the crevices of the bark. Once
these insects are mature, they will move out of the web that once provided them with
protection. No control measures are necessary. If they are unsightly, spray the
webbed area with a strong spray of water to disperse the insects.
14. My oleander is covered with reddish-orange colored worms with black hairs. They
are stripping my plant of its foliage. What should I do?
Oleander caterpillar can strip a plant completely in one week. Oleander caterpillars
are best controlled before they migrate over the entire shrub. The eggs are laid in the
tips of the leaves. When the eggs hatch, all the little caterpillars are clustered on the
branch tips. It is best to prune out these tips and then step on the caterpillars before
they migrate throughout the entire shrub. All labeled insecticides have proven equally
effective if applied when caterpillars are still small.
15. It looks like something is pruning the twigs on my oak, dogwood, or maple tree.
Every day I find more twigs under the tree and they have all been cleanly cut. What is
doing this?
An insect called twig girdler is the culprit. It lays its eggs in the twigs of popular trees
like maple, oak, pine and pecan, then chews it off so it drops to the ground where the
life cycle will be completed. The only control measure is to clean up the fallen twigs
and burn them. This makes completion of the life cycle impossible and eliminates the
next generation.
16. My crape myrtle has a powdery-like substance on the leaf surface. The leaves then
curl up and die. Is this a fungus?
This is a fungus called powdery mildew. Many crape myrtles are very susceptible to
this disease. Repeated appropriate fungicide applications will be needed throughout
the growing season. Resistant hybrids and/or increased air circulation around the
plant have also been shown to be beneficial.
17. The bark on my Chinese elm is splitting and peeling off, and it is orange where the
bark has come off. Is this a disease?
Splitting and peeling bark and variation in bark color on Chinese elm and other plants
like crape myrtle and sycamore is normal and needs no treatment.
18. This year my azaleas and sycamore leaves got a bleached-out appearance and the
underside of the leaves was covered with black tar-like spots. What causes this?
Both azaleas and sycamore are susceptible to damage caused by an insect called Lace
Bug. Damage results from the insect sucking out cell sap, resulting in mottling of the
leaf. The black tar spots are actually the insect's excrements (frass). Control on
azaleas can be accomplished with recommended sprays. Control on sycamore may be
impractical if the trees are large. If no action is taken, the trees will defoliate early,
but no permanent damage will result.
19. I have a stand of pines on my property. One after another is turning brown and is dead
within two weeks. There is some sawdust at the base of the tree and sap on the trunk.
Can I save my trees?
A serious pest of pine species is the Ips beetle and other pine borers. They attack trees
weakened by natural or man-made conditions such as drought, lightning or root
damage during construction. The adult beetle attacks the pine by chewing through the
bark and laying their eggs. The young larvae feed on the cambium tissue which
girdles and kills the tree.
Insecticide sprays on the trunk will probably not save the tree because of the short
developmental period of the insect and the pre-existing weakness from some stress.
Remove the affected tree and spray nearby uninfested trees with appropriate sprays to
help protect them from attack. The best protection is to keep the pine healthy to avoid
attack.
Fruit Crops
1. Why doesn't my apple tree set fruit?
There are three apple varieties recommended for Florida: Anna, Ein Shemer, and
Golden Dorsett. Most apples are not self-fruitful; for example, when Anna is planted
alone, it will not bear fruit. It is recommended that Anna and Golden Dorsett be
planted together because they bloom at the same time and cross pollination will
occur. Ein Shemer is self-fruitful. You may have a more northern cultivar which is
not receiving enough chilling hours.
2. What pecan variety can I grow here?
The three pecans recommended for Central Florida are Curtis, Mooreland, and
Desirable. However, these are recommended as shade trees and should not be
expected to produce quality pecans. There are several diseases that have significant
effect on the yield and the quality of the nuts. These diseases are more expensive to
control than it would be to purchase the pecans.
3. What plum variety can I grow here?
There are no plum varieties for Central Florida. Plum and other pit or stone fruits
require a certain number of chilling hours in order to get blooms and subsequent fruit
production. The chilling hours required for plums is higher than for some of the other
stone fruits like peach and nectarines which can grow here.
4. Every year I get little worms in my peaches, pears, guavas, and papayas. What are
they and can anything be done?
These are probably the larvae of the Caribbean fruit fly. This pest is a problem on all
fruits which are fleshy and which stay on the tree a long time before ripening. The fly
deposits an egg just below the surface of the skin and the larvae feeds throughout the
fruit as it matures. Upon maturity, a fly emerges from the fruit. The larvae are usually
so numerous the fruit is inedible. Frequent and persistent appropriate sprays
throughout the fruiting period will give only poor results in controlling this pest.
5. Why aren't my blueberries growing well?
Most likely your pH is too high. Blueberries like very acid soil - between 4.5 and 5.5.
Most of the soil in our area is not naturally this acid, but we can acidify the soil by
fertilizing with an azalea/camellia fertilizer or ammonium sulfate.
6. How do I fertilize citrus?
Citrus is to be fertilized three times per year: February or March, May or June, and
October or November at the rate of one pound per year of the tree's age with a
maximum of thirty pounds per year application.
A 6-6-6 or 4-6-8 citrus special with minor elements or trace elements would be the
recommended analysis. Apply the fertilizer to the entire rooting area which extends
from the trunk out to several feet beyond the drip line of the tree.
7. Why are citrus fruits splitting? What can I do about it?
The fruits are splitting because of water stress. Too much water in the later stages of
fruit maturation will cause the flesh to expand beyond the capacity of the rind.
Hamlin and Valencia and young trees are more prone to splitting than other varieties
and older trees.
To lessen this as much as possible, it is important to water citrus when adequate
rainfall is lacking and fertilize as recommended to produce a tougher rind.
8. I get lots of citrus bloom but relatively few fruit, what is the problem?
Citrus must be planted 3-4 years before it can reach a stage mature enough to set fruit.
It may bloom prolifically, but until it is mature and established, it will drop its
blooms. Also, citrus generally only sets 1 to 2 percent of the total bloom.
9. Should I mulch citrus?
Mulching is an excellent practice for most plants, but not for citrus. Citrus is very
susceptible to a disease called foot rot which causes peeling bark at the soil surface
and root rot. Mulching citrus encourages this disease.
10. The leaves on my fig tree turn spotty brown and drop. What is the problem?
Fig rust is a very common disease on figs. The rusty foliage that drops should always
be raked up and disposed of since the spores on the fallen leaves can infect new
unaffected leaves on the tree. There are no EPA approved fungicides for figs grown
in Florida.
Environmental Horticulture - Houseplants
1. My weeping fig tree in my living room was beautiful and full, but now it is dropping
all of its leaves. What is the problem?
Excessive leaf drop on ficus is usually due to some unfavorable environmental
condition, which results when ficus is taken from ideal greenhouse conditions and put
into less favorable household conditions. Low light and water stress are usually the
major contributing factors of leaf drop. Check to see if you can purchase acclimated
plants in the area suitable for your light level.
2. I can never get interior palms to do well in my home. Are they hard to grow?
Interior palms are not hard to grow; however correct palm selection is critical. Most
plant retailers will sell Areca palms as interior palms. However, they will perform
poorly inside the home. Chamadorea palms look very similar and yet they grow and
thrive nicely under low light and other adverse conditions found inside the home.
Bamboo and Parlor palms are two Chamadorea type palms. You may also need to
check for spider mites.
3. My fern have small white scales. What can I spray them with?
Ferns are so sensitive to insecticide that most chemicals may do more damage to the
plant than the insect. Even some of the appropriate sprays may cause phytotoxicity.
Ivory soap may help as insects are repelled as well as killed.
4. My African violets look very healthy but they don't bloom. What could the problem
be?
Healthy African violets that fail to bloom are not receiving enough light. African
violets require 1000 foot candles of light for 8 to 12 hours per day. Lower light levels
for longer periods of time are also satisfactory. This light can be provided by natural
sunlight or fluorescent lamps. Night temperatures above 75°F will also reduce flower
production in African violet. They prefer evening temperatures of 65-70°F.
5. The tips of my spider plant leaves turn brown and shriveled. What causes this?
Spider plants are sensitive to fluorine in the city water and boron in fertilizers and the
result is brown or reddish foliage tips. There is no control for this sensitive reaction in
some foliage plants.
6. What is good potting media for my houseplants?
A good potting media for most interior foliage plants is 2 parts of a "ready to use"
sterile potting mixture and 1 part perlite or coarse sand. There are also many prepackaged sterile mixes on the market which may be suitable. It is important that
proper drainage, aeration and moisture holding capacity be provided for most interior
foliage plants.
7. My petunias are wilting and collapsing even though I have watered adequately. What
is the problem?
Damping off is a disease that commonly affects petunias and other bedding plants.
This soil borne disease characteristically causes a browning & collapsing of the stem
at the soil level. Soil fumigants, applied prior to planting according to label directions,
have proven effective. Several fungicides are labeled but may be difficult for
homeowners to find.
8. My ferns have brown spots on the underside of the foliage. Is this an insect or
disease?
These brown spots are spore masses, not insects or disease. These spores are the
equivalent to seeds in higher plants. Fern propagation from these spores is very
difficult since exact and controlled conditions are difficult to simulate for most home
gardeners. Division of the parent plant is recommended for fern propagation, except
tree ferns.
9. How do I get my Christmas cactus to bloom?
Both temperature and day length affect the flowering of these cacti. If night
temperature is maintained between 50-55°F, flower buds will form regardless of day
length. If the temperature is above 55° but below 70°, 13 hours of uninterrupted dark
will cause buds to set. If temperatures are between 70-80°F, 15 hours of uninterrupted
dark will set buds. The short day treatment should continue until buds are well
developed. (6-9 weeks).
10. Why do the buds on my Christmas cactus drop?
Flower bud drop results from rapid changes in growing conditions such as a sudden
drop in temperature or light. Other causes include soil that is kept too dry or too wet,
exposure to cold drafts or high night temperature.
Vegetable Crops
1. My squash fruits get about 3-4" long, then shrivel up and die, what is the problem?
This is a pollination problem. A small squash always subtends a female bloom. It will
begin to develop and may reach the size you have described, 3-4", without being
pollinated. If it is pollinated, it will continue to develop. Pollination of cucurbits
requires bees. Bees may not be present or they may be killed by some insecticides.
Hand pollination of the female bloom can be done when bees are absent.
2. What causes hard white or colorless spots around the outside of my tomatoes?
This damage may be done by stinkbugs. These pests insert their mouth part below the
tomato skin and suck out the tomato sap. These empty cells create a hard, colorless
spot. Stinkbugs do cause fruit to have a poor aesthetic quality, but the fruit is still
edible. Whiteflies cause a similar disorder, but the colorless area is broader and more
generalized. Other similar spots are known as ghost spots, cause unknown.
3. Why do my tomato plants consistently drop their blooms?
This is a problem associated with several factors:
(A) Variety selection is of utmost importance for all crops, including tomatoes.
Varieties other than those that are recommended for this area by the University of
Florida may not be adapted to the climate or soil conditions. Poor growth, bloom
drop, and poor fruit set is to be expected from varieties not recommended for this
area. 'Solar Set' is a variety that sets fruit under higher temperatures than other
varieties.
(B) High nitrogen will cause a lack of blooms or bloom drop. High nitrogen
availability will cause plants to grow excessive and lush foliage at the expense of
bloom and fruit set. Reduce the nitrogen applied to the crop.
(C) Tomatoes have a very narrow optimum temperature range which is best for bloom
set and for production. Nights which are too cool or too hot will cause the bloom
to drop due to abortion of the pollen tube. Cherry types and 'Solar Set' are able to
set fruit at a wider range of temperatures.
Planting tomatoes or any crop out of season is a common error and puts the plant
under environmental stress resulting in poor growth and unwanted flowering
(example: collards), or lack of flowering (example: tomatoes).
(D) A water cycle which subjects the tomato plant to a wet then dry condition as
opposed to a consistent moist condition results in bloom drop. This problem is
very common in container grown vegetables.
(E) Tomatoes require at least 6 hours of full sun. If tomatoes get less than 6 hours of
full sun, poor blooming or bloom drop can occur.
(F) A severe infestation of flower thrips results in bloom drop.
4. After my seeds germinate and start growing the little seedling just turns brown and
collapses at the soil level. What is the problem and how can I treat it?
This is a disease called damping off. It is caused by soil borne fungi such as
rhizoctonia and pythium. There is no treatment for this disease once the seeds are
planted. Soil sterilization is one form of prevention and treatment against this disease.
Soil sterilization can be accomplished by solarization. Use seeds treated with a
fungicide for further prevention. Crop rotation also helps.
5. My okra and other vegetables were not growing well and when I pulled them up, the
roots were covered with tumor-like growths? What is this?
The knots that you see are probably the result of a nematode infestation. Nematodes
parasitize the plant by intercepting water and nutrients which would normally support
active, healthy plant growth. The best treatment for nematodes is soil sterilization by
solarization prior to planting. This may need to be repeated at the start of all
gardening seasons. Adding liberal amounts of organic soil amendments helps, as does
crop rotation. Some varieties are more tolerant to nematodes than other varieties.
Examples are 'Better Boy' tomato and 'California Black-eyed #5' southern peas.
Nodules on the roots of leguminous plants such as beans or peas probably are not
from nematodes but rather from beneficial nitrogen fixing bacteria.
6. When I plant my onions all I get are green onions - they never bulb - why is this?
There are two reasons why onions do not bulb ê Onion sets are usually of the non-bulbing type and most often will only produce
green onions. You should start with seeds or seedlings of bulbing varieties to get
bulbs.
ê
Planting too late in the crop season reduces bulbing. Bulbing onions need to be
planted in the fall and harvested in the spring. Onion tops need exposure to long
nights and cool temperatures to stimulate the bulbing process.
Garlic, like onions, is a short-day crop and should be planted in the fall and harvested
the following spring.
7. The bottom of my tomatoes have dark brown, rotten spots. What is this and how can I
prevent this problem?
This is a nutritional disorder called blossom end rot. The deficiency may result from:
(1) Soils being deficient in available calcium. Soil pH should be 6.0-6.8. A pH lower
than 6.0 may not supply enough available calcium, therefore, lime must be
applied according to a soil test. When the pH is okay, but the level of calcium in
the soil is low, a non-liming source of calcium (gypsum) may be helpful when
applied.
(2) Infrequent watering will disrupt the flow of soluble calcium to the developing
fruit. Soil must be kept consistently moist to keep calcium in solution and
available to plants.
(3) Soluble sprays of calcium to the foliage can help correct the calcium imbalance.
8. I understand that if I plant different cucurbits in the same garden area that cross
pollination will occur. Will I get unusual fruit?
Cucurbits of the same species will be cross pollinated very easily, however, it will not
be expressed in that season's fruit. The results of such a cross would show up if seeds
are saved from that season's fruit and then planted. Therefore, do not collect seeds
from your vegetables, especially cucurbits, for planting in the next gardening season,
unless you are prepared for the surprises.
9. I planted vegetable seeds, but nothing came up. What happens to them?
(1) Some insects such as mole crickets like to eat the seeds. Use an insecticidal bait,
or when tunnels from these insects are seen, drench the soil with appropriate
pesticide and replant. Tunnels also dry out the soil.
(2) Too deep - Seeds that are planted too deep may germinate but may not have
enough food reserves to make it to the soil surface. A general rule for determining
seed depth is never plant a seed any deeper than 1 2 times the seed width.
(3) Too wet soil - Too much water may cause the newly germinated seedling to
develop diseases such as damping off before it ever reaches the soil surface.
(4) Too dry soil - All seeds require moisture to germinate. However, some seeds, for
example - beets, must be kept continually moist or germination will not occur.
(5) Too hot for some seeds or too cold for others prevents germination.
(6) Old seed; seed stored improperly; diseases; birds; and/or mice.
10. Can I grow asparagus in Florida?
Asparagus is not well adapted to Florida due to our environment (mainly
temperature). For good asparagus spear production, a dormant period is required.
Such dormancy is usually brought about by cold weather or drought. Since Florida's
climate is not suited to create a dormant period, growth is more or less continuous
resulting in weak, spindly spears. However, many gardeners are satisfied with the
crop of spears that they do get by persevering.
Environmental Horticulture - Turf grass
1. What is the best fertilizer for my St. Augustine grass lawn? How often should I
fertilize it?
It is recommended that your St. Augustine grass lawn be fertilized a minimum of
twice per year (in the spring and late summer) with a complete fertilizer such as 16-48 or 12-4-8. If nitrogen is applied in summer, a slow release source is suggested.
Summer fertilization with high rates of soluble nitrogen can increase chinch bug
damage, gray leaf spot disease, and excessive rapid growth which can contribute to
thatch.
2. Every winter my lawn turns brown, but I have noticed some lawns in my
neighborhood remain green all year. What grass is this?
The permanent lawn grasses used in Florida are warm season grasses which turn
brown at the first frost. To produce a green winter lawn, you can overseed your
established lawn with a cool-season grass called ryegrass. This should be planted at
the end of October or early November.
The seed should be sowed at a rate of 5-15 lb./1000 sq. ft. Regular mowing,
fertilizing and watering are necessary to maintain a ryegrass lawn during winter.
3. How often should I water my grass? And when is the best time of the day to do this?
It is nearly impossible to say how many times a week a lawn should be watered since
so many factors will influence this. Thus, it is best to water on an as-needed basis
when the grass shows signs of stress from a lack of water. Some of those signs are:
ê The grass color will be a bluish-gray rather than a clear green.
ê Footprint impressions will remain for a long time (approximately one minute)
when the grass is walked on.
ê Grass blades will fold in half.
ê Soil samples from the root zone feel dry.
A general rule for watering is to apply 3/4" of water when grass shows these signs of
stress which often requires two to three times per week in the summer and once every
ten to fourteen days in the winter. The best time for lawn irrigation is in the early
morning hours to avoid prolonging the dew period which can encourage disease
problems.
4. I haven't been able to find St. Augustine grass seed. Do you know where I can get it?
Current varieties of St. Augustine grass do not produce viable seed, therefore it must
be established by vegetative propagation - sprigs, plugs, or sod.
5. What type of grass will grow in my shady lawn?
All of the turf grasses that are grown in Florida require full sun except Centipede grass
and several varieties of St. Augustine grass: Seville, Bitterblue, Jade, and Delmar.
Seville, Jade, and Delmar have a semi-dwarf growth habit while Bitterblue has a normal
growth habit. However, neither will take dense shade. Maintaining as high of a mowing
height as possible will encourage turf growth in moderate shade.
In densely shady areas, planting a shade loving ground-cover or mulching, instead of
turf grass, is recommended.
6. Every spring my Bahia grass lawn develops yellow spots even though I fertilized,
what causes this?
These yellow spots indicate iron deficiency in Bahia grass. In spring, Bahiagrass
grows so rapidly that it cannot keep up with its own nutritional demand for iron. It is
best to make supplemental iron applications and avoid heavy fertilization or a
fertilizer high in water soluble nitrogen since this will encourage excessive growth
and increased demand for iron. Keep in mind that insects, diseases, high pH, and soil
compaction can also cause yellow spots in the lawn so rule these problems out first
before making a recommendation. Centipede grass and sometimes St. Augustine
grass, also have problems with iron deficiency.
7. When should I reseed my Bahia grass lawn? I have had trouble getting the seed to
grow.
The best time to seed is from April through June since this permits a full growing
season before cold weather and takes advantage of the rainy season.
Poor germination can be caused by a couple of factors: Germination of Bahia grass
seed is often slow and erratic because of a hard waxy seed coat, therefore, buy only
scarified seed (seed mechanically treated to increase the germination rate). Bahia
grass must also be covered with soil and kept constantly moist in order to encourage
germination.
8.
I have read about this wonderful miracle grass called Zoysia grass. Is it as good as
the advertisement says?
Due to several over-enthusiastic promotions and advertisements, the public has been
misinformed on the merits of zoysia grasses. Zoysias have advantages and
disadvantages like all Florida lawn grasses.
The improved zoysias have to be propagated vegetatively and are extremely slow in
becoming established. Two growing seasons may be required for coverage of the
lawn when propagated by plugging or sprigging. Zoysias produce a heavy thatch
which requires periodic renovation. Other disadvantages include: slow recovery from
damage; requires a reel mower; high fertility requirement; need for frequent
irrigations; can be severely damaged by nematodes, hunting billbugs, and several
diseases. The University of Florida does not recommend this as a viable lawn grass in
Florida except for those with ample time and financial resources to provide the
intense maintenance practices required to grow desirable Zoysiagrass.
9. I can control most of the weeds in my lawn, but I always have difficulty with grassy
weeds. Any suggestions?
Weed killers that are labeled safe for grasses usually will not kill grassy weeds
because their structures are too similar. A pre-emergent herbicide will prevent the
germination of annual, grassy-type weeds and any other weeds that grow annually
from seed. Pre-emergent weed killers are applied before weed seeds begin to
germinate in early spring and/or early fall.
10. Should I leave my grass clippings on the lawn or should I have a catch bag on my
mower?
If you are mowing frequently enough, it is best to leave the clippings on the grass. By
leaving the clippings on the ground they will decay and the nutrients in them will be
reused by the turf. Mow often enough so that not more than 1/4 or 1/3 of the total leaf
surface is removed at a given mowing.