Collard Flash Seedling Tray

For best results with Collard Flash, grow one seedling plug per 1801-cell or 4-inch container. Use well-drained, rich soil with a pH of 6.0-6.5, light feed (75-125 ppm), and temperatures between 50-65. Provide consistent moisture and full sun. Watch for cutworms, cabbage loopers, cabbage worms, flea beetles, root maggots, black rot, downy mildew, clubroot, and alternaria. 

Like lettuce, Collard Greens form small yellow flowers along a stalk when they bolt in excessive heat. These flowers are edible, but indicate the end of harvesting. Grow this plant in cool weather to avoid bolting and extend the harvesting season. 

This plant doesn't require pinching.

Space containers for adequate airflow and sunlight penetration around the base and foliage of each plant.

Combine a few techniques to keep Collard seedling plugs from stretching tall. 

1. Provide adequate space between plants.

2. Grow plants with the proper amount of light.

3. Maintain an optimal temperature of 50-65 degrees. 

4. If height control is an issue with this plant in your greenhouse, pinching can promote bushier growth.

We don't recommend using chemical growth regulators for vegetables. 

Scout for cutworms, cabbage worms, cabbage loopers, flea beetles, and root maggots as part of your commercial greenhouse's Integrated Pest Management program. Use floating row covers on your Brassica vegetables to prevent significant pest problems. 

Cabbage loopers are green caterpillars that feed on Brassica leaves. The best methods of controlling their population include using floating row covers to prevent adult moths from laying eggs on plants; introducing natural enemies, including lacewings, ladybugs, and parasitic wasps; applying Bacillus thuringiensis (Bt); handpicking caterpillars off of plants; or applying a chemical insecticide.

Cutworms are moth larvae that eat seedlings at the soil level, causing plants to wilt and die. Control cutworm populations by removing weeds and debris that allow cutworms to hide; introducing parasitic nematodes and predatory wasps; using cardboard or metal collars around the base of seedlings to prevent access; handpicking and removing worms from the soil and plants; or applying insecticide bait around plants.

Cabbage worms are the larvae of the cabbage butterfly. They feed on Broccoli leaves and other brassica vegetables, causing holes and tattered leaves. To control cabbage worms, use floating row covers; introduce natural predators, including ladybugs, lacewings, and parasitic wasps; handpick and dispose of the larvae; or use Bacillus thuringiensis (BT) insecticide.

Flea Beetles are a jumping insect which eats Brassica vegetables and other plants, creating tiny holes in the foliage which can reduce yields and stunt growth. Rotate crops, remove plant debris, and monitor plants to decrease the likelihood of an infestation. Introduce parasitic wasps as a natural enemy, use floating row covers, or physically remove beetles from plants. As a last resort, apply an insecticide labeled for flea beetle control, rotating between products to prevent resistance. 

Root Maggots are larvae of a particular fly species that feed on plant roots, leading to wilting, stunted growth, and reduced yields. Rotate crops, keep the greenhouse clean, and destroy any infested plant material to prevent spread. Beneficial nematodes and parasitic wasps can help control root maggot populations. Prevent adult flies from laying eggs on plants with floating row covers or by drenching soil with insecticidal soap or neem oil. As a last resort, use an insecticide labeled for root maggot control when adult flies are active.

Collard Greens are prone to typical Brassica diseases, including black rot, clubroot, downy mildew, and alternaria. The best ways to prevent the spread of disease is to acquire seedlings and seed from a trusted source, to sanitize all surfaces, containers, tools, and equipment before each use, and to use a sanitary growing media. 

Black Rot is a bacterial disease that destroys cruciferous vegetables. Xanthomonas campestris pv. Campestris leads to V-shaped yellow lesions on foliage, wilting, and blackening. Start with disease-free seeds or seedling plugs and sanitized equipment, tools, and surfaces in your commercial greenhouse. Rotate Brassica crops yearly to reduce disease pressure and remove and destroy any infected plant material. If you choose to use chemical control, apply a preventative spray of a bactericide labeled for black rot control at transplant and as needed during the growing season.

Clubroot occurs when the parasitic organism Plasmodiophora brassicae spreads via soil or improperly produced compost. It infects Brassica roots, which causes them to swell and prevents them from absorbing water or nutrients, leading to stunted and destroyed plants. The pathogen can live in soil for up to 20 years, causing the most problems in wet, acidic soils. Prevention is the best treatment for this disease. Inspect transplants before planting them in the garden, clean and sanitize tools after each use, and be sure compost reaches 148℉ before adding it to the garden. If clubroot becomes a problem, remove Brassicas from the area for five to seven years to decrease the pathogen population and use resistant varieties to reintroduce Brassicas to the infected ar

Alternaria is a fungal disease that causes foliage yellowing, browning, and necrosis, leading to defoliation. Sanitize surfaces, remove infected plants and debris, and use clean planting media. Copper-based fungicides or those with active ingredients azoxystrobin, mancozeb, or chlorothalonil are effective against alternaria. Prevent infection by watering at the base of each plant, providing good ventilation, spacing plants appropriately, and controlling humidity levels in the greenhouse. Some plant varieties are resistant to this disease.

Downy Mildew is a disease caused by Peronospora sparsa, a fungus-like organism that causes white or gray growth on foliage undersides and yellowing of the leaf surface. Use proper sanitization, ventilation, and humidity control. Remove infected plants and debris to control the spread. Don't use overhead irrigation, and apply a fungicide if needed. Azoxystrobin, chlorothalonil, mancozeb, and fenamidone are effective in a rotation against a severe outbreak of Downy Mildew.

We recommend planting one seedling plug per 1801 cell or 4-inch container. Use a well-drained soil in full sun and completely bury the ellepot in the center of the container. Handle the roots carefully, spreading them out in your final container. Water the seedling to provide even moisture and dispel air pockets. Cellpacks finish in one to two weeks.