Container Gardening Complete

Job:06-700309 Title: CPS - Container Gardening Complete

700309 - ContainerGardens_001-272_FINAL.indd 210 5/24/17 12:21 PM
Job:06-700309 Title: CPS - Container Gardening Complete
Job:06-700309 Title: CPS - Container Gardening Complete

700309 - ContainerGardens_001-272_FINAL.indd 211 6/5/17 3:12 PM

210 chapter 4

Botrytis or Gray Mold

(Botrytis spp.)

Description: The botrytis fungus is probably

the costliest disease in the greenhouse industry

because it affects such a broad range of plants,

and it can damage almost any part of the plant,

including the leaves, stems, flowers, fruits, and

buds. It is fast growing and spreads rapidly, and

often enters through an injury site. Botrytis first

appears as white to gray splotches on the leaves

with fuzzy or dusty spores clearly visible. These

spores spread via water, wind, and physical

contact. Rot eventually forms on the infected

tissue, leading to complete bud, leaf, stem, fruit, or

flower rot.

Plants affected: Botrytis affects thousands of

different plant species but is quite common

on geraniums, strawberries, grapes, cyclamen,

chrysanthemums, roses, dahlias, and peonies.

Solutions: Remove and dispose of any infected

tissue. Make sure all your pruning equipment is

sanitized after working on a plant with a botrytis

infection. In addition to overwintering in the

soil and on stem and leaf tissue, botrytis may

also overwinter on infected fruit left clinging

to branches and plants, so remove all infected

berries and fruits at the end of the growing

season. Copper-based organic fungicides, as well

as those based on Bacillus subtilis and potassium

bicarbonate, are effective controls.

Botrytis, along with a handful of other fungal

issues, is a common problem on ripening

strawberries. One of the easiest ways to prevent

these fungal diseases is to grow strawberries in

containers. Sterile potting soil is pathogen-free

and gives strawberry plants a good start. And, as

long as you don’t put your containers too close

together, growing strawberries in pots helps

improve air circulation around the plants as well,

allowing the fruits to dry more quickly after rain

and allowing you to have better control over

plant spacing.

PHYSIOLOGICAL PROBLEMS

Occasionally a problem may crop up in your

container garden that has nothing to do with

an insect or pathogen, but instead is the result

of something in the environment. Physiological

disorders can be attributed to things like poor

light levels, road salt exposure, hail or frost

damage, herbicide injury, sunscald, drought, or a

nutrient deficiency.

Here are a few physiological problems you may

encounter occasionally in your container garden.

Cracked tomatoes. A problem tied to moisture

levels, skin cracking most often occurs just

after a period of heavy rainfall, primarily after

a prolonged period of dry weather. The plant

uptakes water from the soil, and it collects in

the developing fruits. The skin can only expand

to hold the excess moisture for so long before

it cracks open. Some tomato varieties are more

prone to cracking than others. Cracked fruits

should be eaten within a day or two of harvest,

and you may find they have a more diluted flavor.

Blossom-end rot. This disorder appears as

a sunken, dark lesion on the bottom-end (or

blossom-end) of the developing fruit. Tomatoes,

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Troubleshooting 211

peppers, and eggplants develop blossom-end rot

when there is a lack of calcium in the growing

fruit. The trouble is not necessarily that your soil

is calcium-deficient, but rather that the calcium

can’t get into the plant. Calcium comes into a

plant with water, and when plants are subjected

to dry periods, the calcium cannot move into

the fruits. This leads to a calcium deficiency

and blossom-end rot. The key to staving off this

disorder is proper mulching and watering. Do

not allow your containers to completely dry out

between waterings. Consistent soil moisture is key.

Hollow potatoes. If you slice open a homegrown

potato and there’s a hollow spot in the center,

it’s often due to environmental or nutritional

stress. Periods of slow growth followed by periods

of fast growth are often to blame. This growth

pattern may be the result of heavy rains after

a prolonged dry period or even a mid-season

fertilizer application. To prevent “hollow heart” in

container-grown potatoes, mulch the container

well and use a fresh blend of potting soil and

compost to fill the containers every year. Make

sure the containers receive consistent moisture

throughout the growing season.

Curled leaves. Leaf curl is a physiological

problem often related to fluctuations in moisture

levels. For many tomato varieties, curling up

Blossom end rot is the result of inconsistent irrigation. It appears as a sunken, dark lesion at the bottom end of

tomatoes, peppers, and eggplants.

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