Cool-Season Plant Problems and Solutions

Irish bells and alstroemeria bloom together.

Thin thickly-sowed greens eaten whole (except for the root) offer a bit of a bite raw in salads, or make wonderful additions to stir-fries.

Species stock are single-petaled and red-purple and exquisitely scented. I relish their self-sowing throughout the garden.

Tatsoi bolting (sending up it's flower stocks) are still completely edible, from base leaves to tips of flower heads.

Beautiful "butterflies" iris prefers shelter from late afternoon sun.

Solanum potato vine's rich blue-purple blossoms.

Richly colored nasturtium.

Transplant tomato plants to topknot of branches, removing those below the soil, to encourage more extensive root system. However, do this ONLY with tomatoes, not any other plants - plant everything else at the same depth it is in the container you purchase it or grow it.

Once tomatoes reach about 18" tall, about the second rung on metal cages, they've developed enough of a root system to allow you to let blossoms remain on the bushes to set fruit. I do this with my Sungold tomatoes, but wait even longer with other varieties because I want to give them even more time to develop really extensive root systems so they'll be extremely strong by the time the heat hits and they begin to actually set fruit.

First rose blooms.

Lovely lavender.

Blooming bladderpod already has some seedpods.

Fig fruits set on wood grown last year. This is the "bebra" crop. More figs will set on the wood that grows this year and ripen later this summer. Two crops!

Wonderful peachy rose bloom.

Salvia blooming year round.

Turquoise Ferraria crispa.

Calla lily and Iochroma coccinea.

    We're getting to the end of our cool growing season, with perhaps two more months of coolness before summer's heat blasts its way through our gardens.  Perhaps you've had some of the primary problems listed here regarding the main veggies we grow during the cool season, so you can benefit from some of the solutions.  If nothing else, you'll be aware of some things that may appear in future gardens, and now you'll know how to deal with them! ​
 
Asparagus

PROBLEM:   Plants  that turn tan or brown from their tops downward  have  been attacked by the asparagus beetle.
SOLUTION:   Hose  off  plants with a strong stream of water  to  dislodge  the beetles.   Remove and destroy the beetles and their larvae as soon as they are noticed.   Spray heavy infestations with rotenone.   Rotenone kills beneficial insects also,  so use only for really major infestations.   Plant tomatoes  as repellents.
 
PROBLEM:   Stems  and branches with reddish-brown spots have been infected  by asparagus rust.   The entire plant yellows,  weakens,  and dies.   Rust  needs dampness to germinate.
SOLUTION:   Plant resistant varieties.   Avoid damp or low-lying  areas.   Cut tops close to the soil, and destroy (don’t compost) them.
 
PROBLEM:   If  spears are thin and weak or do not come up at all,  the  plants have  been  weakened  by poor cultural care,  previous attack  by  insects  or disease, frost or drought, or they have been harvested too heavily previously.
SOLUTION:   Fertilize and irrigate the plants adequately.   Control damage  by pests  and  competition with weeds.   Mulch soil to protect  the  plants  from freezing  or  drought conditions.   Do not harvest until spears are  from  one quarter to three-eighths inch wide.  Limit harvest to allow plants to recover.
 
PROBLEM:   Spears that are tough are too mature,  or perhaps the soil was  too acid or not fertile enough.
SOLUTION:   Harvest when the spears are six to eight inches long.  The  plants are  heavy  feeders,  so  mulch them with lots of manure during  the  fall  or winter.  Rains and irrigation will then wash "manure tea" down to the roots. 
 
Beets

PROBLEM:   A  cracked root results from sudden growth after  heavy  irrigation following drought conditions.
SOLUTION:   Irrigate deeply and more frequently to keep soil evenly moist.   Provide organic mulches  to help retain moisture.
 
PROBLEM:  If the root is chewed,  root maggots or wireworms have been enjoying your beets.
SOLUTION:  Incorporate wood ashes into the soil.
 
PROBLEM:   Root is not sweet-tasting and become stringy and woody  when  it is  too mature or has matured late in the summer,  or when they haven't been watered adequately.
SOLUTION:  Water deeply and more frequently.  Harvest when roots are no larger than  one to two inches in diameter.   Plant them so that they  mature  during cool weather.
 
PROBLEM:  Roots that are too small have been sown too closely together. 
SOLUTION:   Each seed is a composite that will develop into several beets,  so allow enough  space when sowing,  and thin and eat the young beets.  Young beet greens make excellent raw or cooked additions to salads.
 
PROBLEM:   Roots  with  internal black spots suffer from a  boron  deficiency, which is most prevalent in dry, alkaline soils that are high in calcium.
SOLUTION:  Incorporate some borax into the soil.  
 
Cabbage Family:  Broccoli, Brussels Sprouts, Cabbage, Cauliflower, Kohlrabi

PROBLEM:   Plants  that wilt and fall over and have tunneled stems  and  roots have been feasted upon by the cabbage root maggot. 
SOLUTION:  Plant seeds early in the fall so they develop into large,  vigorous transplants  that  overwinter well and can be harvested early in  the  spring.  Protect seedlings with cheesecloth cover to prevent the adult black flies from laying their eggs in the surrounding soil.  Place collars around  transplants.  Dust with a mixture of lime and wood ashes or with diatomaceous earth - but be certain  to purchase only the type sold for garden use,  not that labeled  for swimming pool use.  Interplant with mint, rosemary, sage, and tomato.
 
PROBLEM:  When plants are stunted,  leaves yellow and wilt, and roots are misshapen and enlarged with club-shaped knots that rot and become slimy, clubroot is the problem. 
SOLUTION:   Plant healthy transplants of a resistant variety.   Rotate  crops.  Maintain  soil  pH  above 7 by sprinkling wood ashes around the  base  of  the plant. 
 
PROBLEM:   Plants  with foliage edges that appear burnt have been affected  by water stress and calcium deficiency,  especially on dry soils which are acidic or high in potassium.
SOLUTION:   Provide  plants  with sufficient water to  maintain  their  steady growth.   Calcium is not available to plants at a low pH.  Dolomitic limestone is a good source of lime and magnesium.  The finer the grade of the limestone, the faster it can break down in the soil, raise the pH, and enable the calcium to be utilized.   Incorporate bone meal,  gypsum,  and plant residues.  Rotate crops.
 
PROBLEM:   Cabbage  or brussels sprouts heads suddenly split  when  they  have grown  suddenly as a result of too much fertilizer or water after a  prolonged dry period, making the inner leaves grow faster than the outer leaves, so bursting their way through. 
SOLUTION:  Do not allow the soil to get too dry.   Apply water slowly at first after a dry period.
 
PROBLEM:   Cauliflower  heads  that look cracked and may have  leaves  growing through  the head may be overmature or subjected to excessive nitrogen or  hot or dry weather. 
SOLUTION:   Do not let the soil dry out.   Plant varieties appropriate to  the area so that they mature before the weather gets too hot.
 
PROBLEM:   Cauliflower  forms  heads when the plants are still  small  if  the weather gets too warm before there is sufficient plant development.
SOLUTION:   Plant earlier in the season so that plants can mature before  warm temperatures trigger heading.
 
PROBLEM:  If cauliflower heads are only the size of buttons,  nitrogen  deficiency or poor drainage may be at fault.
SOLUTION:  Apply a nitrogen fertilizer, and aerate the soil to improve drainage for the next crop.  The tiny heads won’t get any larger.
 
PROBLEM:  Cauliflower heads that are brown, stunted, deformed, hollow-stemmed, or with pithy cores may be suffering from boron deficiency.
SOLUTION:  Apply a complete fertilizer with micronutrients.
 
PROBLEM:   Cauliflower heads that turn yellow or brown have been sunburned  or frosted. 
SOLUTION:   Plant  cauliflower so that they mature before the  first  expected frost.   When the head is three inches across,  tie the outer leaves up around it, and harvest it from four to seven days later.
 
PROBLEM:   Foliage  that is deformed,  wilted,  and has whitish  or  yellowish spotting has been infected by the harlequin bug.
SOLUTION:   Handpick  and  destroy adults and egg  clusters.   Control  nearby weeds.  For severe infestations, spray with pyrethrum, rotenone, or sabadilla.  Rotenone  and  sabadilla kill beneficial insects also,  so use them  only  for really major infestations. 
 
PROBLEM:   Large ragged holes in the foliage and the presence of green  caterpillars indicate the presence of cabbage worms.
SOLUTION:  Handpick and destroy worms and egg clusters.  Spray with Bt (Dipel, Thuricide,  Biotrol) every seven to ten days.  The adult white butterfly moths will be deterred by planting hyssop,  pennyroyal,  rosemary,  sage, thyme, and wormwood.   Spray a diluted solution of ground leaves of these plants onto the crops,  reapplying after rains or overhead irrigation.  Spread cheesecloth over the crops and anchor it at the soil level to keep the moths from reaching  the crops to lay their eggs.
 
Carrots

PROBLEM:   Roots that are hairy,  forked,  or misshapen have been overwatered, overfertilized, or grown in rocky or cloddy soil. 
SOLUTION:   Plant  in raised beds.   Incorporate compost to lighten  soil  and improve drainage.
 
PROBLEM:   Cavities  in roots indicate water stress  and  calcium  deficiency, especially on dry soils which are acidic or high in potassium.
SOLUTION:   Provide  plants  with sufficient water to  maintain  their  steady growth.   Calcium is not available to plants at a low pH.  Dolomitic limestone is a good source of lime and magnesium.  The finer the grade of the limestone, the faster it can break down in the soil, raise the pH, and enable the calcium to be utilized.   Incorporate bone meal,  gypsum,  and plant residues.  Rotate crops.
 
PROBLEM:   Roots  that grow twisted around one another have been  planted  too closely together.
SOLUTION:  Sow carrots more thinly.  As they grow, thin them to an inch apart. 
 
Celery

PROBLEM:  Stunted plants with greenish or water-soaked spots on the leaves and sunken lesions on the stalks are infected by blight, which is favored by cool, moist weather, and easily spread by splashing water droplets. 
SOLUTION:   Use clean seed of resistant varieties.   Oversow seed that is more than two years old to compensate for lessened viability.   Avoid handling  wet foliage.
 
PROBLEM:   Pinkish,  water-soaked  areas on stalks which rot and taste  bitter have pink rot.
SOLUTION:  Plant resistant varieties.  Destroy infected plants.  Rotate crops.  Avoid planting where cabbage, celery, or lettuce has been planted.
 
PROBLEM:  Cracked stems indicate a boron deficiency,  especially in dry  soils with a pH above 6.8.
SOLUTION:  Incorporate lime, manure.  Irrigate deeply and more frequently.
 
PROBLEM:   A blackened central portion identifies blackheart and results  from calcium  deficiency in the young,  rapidly-growing leaves.   This occurs  more frequently  on  dry,  acidic  soils under stressful  growing  conditions - hot weather, alternately wet and dry soil, and high potassium levels.
SOLUTION:  Incorporate bone meal,  gypsum, and organic compost.  Mulch plants, and water deeply and more frequently to maintain high moisture levels.  If the soil  is  high in potassium,  avoid using wood ashes  and  manure.   Dolomitic limestone is a good source of lime and magnesium.   The finer the grade of the limestone,  the faster it can break down in the soil, raise the pH, and enable the calcium to be utilized.  Rotate crops.
 
Lettuce

PROBLEM:  Leaves that are bleached and paper thin have matured in weather that is too hot. 
SOLUTION:   Plant  summer-maturing varieties rather than try to  lengthen  the season for those that should mature in cool weather.
 
PROBLEM:   Tipburn causes foliage edges to appear burnt and results from water stress  and calcium deficiency,  especially on dry soils which are  acidic  or high  in potassium and on hot,  dry summer days after cloudy weather or  heavy irrigation.
SOLUTION:   Provide more regular deep watering.   Calcium is not available  to plants  in soils that are a low pH.   Dolomitic limestone is a good source  of lime and magnesium.   The finer the grade of the limestone,  the faster it can break down in the soil,  raise the pH,  and enable the calcium to be utilized.  Incorporate bone meal, gypsum, and organic matter.  Rotate crops.
 
PROBLEM:  Inner leaves of head lettuce that develop black and slimy edges is due to hot weather. 
SOLUTION:   Plant warm-season varieties for warm-season  maturing,  and  plant cool-season varieties so that they mature in cooler weather.
 
PROBLEM:   Lettuce that tastes bitter has matured when the weather is too hot. 
SOLUTION:   Plant the proper varieties for maturing at different  times.   Sow fewer  seeds at a time,  and sow them  one or two weeks apart,  so  that  they mature consecutively.   Harvest them promptly.  For eating, rinse the lettuce, shake  off  the excess water,  and let it sit in the refrigerator for  several days - the bitterness will dissipate.
 
PROBLEM:  Lettuce that goes to seed before it can be harvested was planted too late in the season.
SOLUTION:  Make successive plantings of varieties appropriate for your area so that they mature in different seasons and levels of light and heat.
 
Onion Family:  Chives, Garlic, Leek, Onion, Shallot

PROBLEM:  Plants send up flower stalks rather than forming bulbs when the bulb sets  were planted when they were too large,  planted too early,  or kept  too warm  for too long prior to planting;  the soil was allowed to become too dry; or there was a period of cold weather after plants were grown in warm  weather for six to ten weeks.
SOLUTION:   Plant  seeds  just before a frost period for a greater variety of shapes, sizes, colors, and flavors.   Plant sets  which  are smaller  than one-half inch in diameter during or after frost  period.   Plant larger bulb sets for use as cool-weather green onions.   These will bolt (send up their seedstalk) with the  slightest  hint of warmth.   Water onions deeply and more  frequently  to maintain their steady growth. 
 
PROBLEM:   Plants stay small and do not produce bulbs if they have been insufficiently fertilized or irrigated,  or they are the wrong variety.   For example, bunching onions don't produce bulbs. 
SOLUTION:   Plant  bulbing varieties.   Apply a balanced  fertilizer  in  late spring,  and  water  onions  well until their tops turn brown and  fall  over, signaling maturation.
 
PROBLEM:   Plants that grow slowly and develop thick necks may result  from  a phosphorous deficiency or excessive nitrogen or water.
SOLUTION:   Incorporate  a  high-phosphorous fertilizer - bone  meal,  finely ground rock phosphate,  fish meal,  manure, compost, cottonseed meal, and soybean meal.  Incorporate organic matter to improve drainage. 
 
PROBLEM:  Leaves striped with yellow indicate a manganese  deficiency,  especially on soils with a pH above 6.7.
SOLUTION:  Incorporate manure.
 
PROBLEM:   Leaves  that  have whitish blotches streaked with silver  may  have thrips.   Heavily infested plants become stunted,  the leaves are bleached and die back,  and the necks grow abnormally thick.   Thrips are worst in hot, dry seasons.
SOLUTION:   Plant  tolerant and resistant varieties.   Dust with  diatomaceous earth.   Spray  with  a soap mixture or rotenone.   Keep the garden  clean  of weeds.
 
PROBLEM:   Leaves that are pale or greenish-yellow may be deficient in  nitrogen, perhaps from leaching out after long, wet periods.
SOLUTION:   Incorporate a high-nitrogen  fertilizer,  blood  meal,  cottonseed meal, manure, or compost.
 
PROBLEM:  Fluffy white rot begins at the base and spreads to the foliage,  and bulbs have a soft watery rot.
SOLUTION:  Destroy (don’t compost) diseased plant immediately.  Rotate crop to new soil.
 
PROBLEM:  Onion maggots tunnel cavities in the lower stem and bulb, and plants may  wilt and die.   Susceptibility is greatest with white varieties,  less so with yellow ones, and the least with red ones.
SOLUTION:  Plant seeds or sets throughout the garden, rather than in one area.  Add sand or wood ashes to the top layer of the planting area.   Spray the soil with  an oil-and-soap mixture.   Dust with diatomaceous  earth.   Destroy (don’t compost) the affected  plant before the maggots mature into flies and lay a new  generation of eggs.
 
PROBLEM:  If plants are stunted and roots are pinkish or red,  shriveled, and rotted,  the  plant  is infected with pink root fungus.   It is encouraged  by heavy, wet soils. 
SOLUTION:  Plant tolerant and resistant varieties on well-drained soil. Incorporate organic matter to improve drainage.   Once the soil is infested, do not grow any bulb crops there.
 
PROBLEM:   Rust  infection  is manifested by long pustules  of  bright  orange spores on the leaves. 
SOLUTION:  The fleshy parts are usually safe for eating,  but the foliage must be destroyed.  Rotate crops to soil that is not as rich in nitrogen.
 
PROBLEM:  Black spots on leaves and between the sections of bulbs indicates  a smut infection.  Young plants may have twisted leaves.
SOLUTION:  Plant healthy, resistant varieties.
 
PROBLEM:  Bulbs that are soft and have thin skins,  thick necks, and leaf tips that turn brown are deficient in potassium.
SOLUTION:  Incorporate a high-potassium fertilizer.
 
PROBLEM:  Bulbs with thin skins are deficient in copper.
SOLUTION:  Incorporate manure with micronutrients.
 
PROBLEM:   Outer  layers of harvested bulbs that become  bleached,  soft,  and slippery demonstrate sunscald damage that occurs when bulbs are harvested  and set out for their initial curing in direct sun on very hot, dry days.
SOLUTION:  Shield bulbs from direct exposure to the sun during curing.
 
PROBLEM:   Mature  bulbs and sets develop sunken,  spongy areas  around  their necks when they are infected by neck rot fungus.  White varieties are extremely  susceptible.   The fungus is encouraged by insufficient curing and  fertilizer that is applied late in the season. 
SOLUTION:  Plant healthy sets of early-maturing,  thin-necked varieties.  Pungent  varieties  are less susceptible than mild-tasting ones.   Do  not  apply fertilizer late in the season.   Incorporate organic matter.  Cure bulbs thoroughly  at warm temperatures with good ventilation but out of the direct  sun.  Store them in a cool,  dry area with good air circulation.   Examine the bulbs frequently,  and remove those that are spoiled.   Store thick-necked varieties separately  from thin-necked ones,  and eat them soon after harvest,  as  they will not cure sufficiently for long storage.
 
Peas

PROBLEM:   Semi-circular  notches  on  the margins  of  leaves  are  tell-tale munchings of the pea leaf weevil.
SOLUTION:  Serious damage occurs only until the six-leaf stage.
 
PROBLEM:   Plants  that  are healthy but don't set blooms may be  affected  by excessive  nitrogen,  a previously heavy set,  or overmature pods  that  still remain on the plant.
SOLUTION:  Flush out excessive nitrogen with a one-time very heavy irrigation.  Keep pods harvested as they mature.
 
Radishes

PROBLEM:   Small roots that grow slowly and have a strong flavor have  matured in hot weather or have not been watered sufficiently. 
SOLUTION:  Water more deeply and frequently.  Plant for cool-season maturing.
 
PROBLEM:  Red varieties that grow slowly,  are pale, and have yellowish leaves are suffering from general nutrient deficiency.
SOLUTION:  Apply a balanced fertilizer.
 
PROBLEM:   Plants with healthy foliage that develop only tiny bulbs were  sown too closely.
SOLUTION:   Allow  more space when sowing,  or thin seedlings  to  two  inches apart.
 
PROBLEM:  Roots that split or are hollow or pithy are overmature.
SOLUTION:  Harvest as soon as roots are large enough.
 
PROBLEM:  Plants bolt (send up their seedstalk) when the days are too long and the nights are too short.
SOLUTION:  Grow in cooler weather of early spring or late fall.
 
Spinach
​
PROBLEM:   Blight,  transmitted  by aphids,  causes plants to be  stunted  and leaves to yellow and curl.
SOLUTION:  Plant resistant varieties, control aphids, maintain weed-free growing areas.
 
PROBLEM:  Plants bolt (send up their seedstalk) when the days are too long and the nights are too short.
SOLUTION:  Grow in cooler weather of early spring or late fall.