Tomato Growing Tips

Tips on Growing Tomatoes in Oklahoma

Allen Robinson: Ask a Master Gardener

Sunday, April 15, 2018

Q: My family loves to eat fresh tomatoes off the vine, but my friends tell me they have trouble growing tomatoes around here. Can you tell me why it is difficult to grow tomatoes here and what I can do about it? Tracy A., Tulsa

A: You are certainly not alone when it comes to loving tomatoes fresh off the vine, as well as having trouble growing them in northeast Oklahoma.

One of the most common issues is known as “blossom drop,” which occurs from poor pollination. Weather is the chief cause of inadequate pollination in garden-grown tomatoes, with the most important factor being temperature. Effective pollination stops occurring once night temperatures are consistently over 70 degrees and/or when daytime temperatures are consistently over 92 degrees, especially if it is windy. Too much rain or too high or low humidity are additional weather factors that reduce pollen fertility. Also, over application of nitrogen fertilizer leads to blossom drop, as well as tall, lanky plants.

The solution to this is to plant healthy plants as soon as possible after the last frost has occurred. Then, pick the fruit as soon as it turns pink and let it continue to ripen indoors. Do not let it sit on the vine until it becomes overly ripened and soft.

Another common issue is called “blossom end rot,” where the fruit develops blemishes on the blossom end of the fruit. This is caused by a calcium deficiency in the plant when the fruit is young. Overwatering, either from nature or the gardener, is the most common cause rather than the lack of calcium in the soil.

Skin splitting, called “cracking,” is also caused by plants going from too little to too much water. Be consistent about watering. Mulch plants to provide consistent moisture at the root level, but do not mulch directly against the plant as it can lead to diseases.

Speaking of diseases, avoid splashing soil upon the plant and onto tomato fruits, as this carries related fungi and bacterial diseases. Instead, either use a soaker hose or drip irrigation system or carefully water at the base of the plants. Avoid damaging tender roots by not hoeing too deeply or too closely to the plants.

In addition, several pests love to live off the stems and leaves of tomato plants. For a listing of pests and how best to battle them, go to tulsamastergardeners.org and search for OSU Fact Sheet EPP-7313 (Home Vegetable Garden Insect Pest Control).

Experts say the best weed control in a lawn is to simply grow a healthy lawn. The same is true for vegetables. Look for high quality varieties at reputable nurseries around town and ask which varieties are the most disease resistant. Several varieties are available.

Tulsa’s climate is a challenge to growing tomatoes in the summer but, with a little attention to details, you can have good success. And, remember, there’s always fall.

Garden tips

Fruit and Nut

• Don’t spray insecticides during fruit tree bloom or pollination may be affected. Disease sprays can continue according to schedule and label directions.

• Control cedar-apple rust. When the orange jelly galls are visible on juniper (cedar), following a rain, begin treating apple and crabapple trees with a fungicide.

• Fire blight bacterial disease can be controlled at this time. Plant disease-resistant varieties to avoid diseases.

• Continue spray schedules for disease-prone fruit and pine trees.

Trees and shrubs

• Proper watering of newly planted trees and shrubs often means the difference between success and replacement.

• Remove any winter-damaged branches or plants that have not begun to grow. Prune spring-flowering plants as soon as they are finished blooming.

• Control of powdery mildew disease can be done with early detection and regular treatment. Many new plant cultivars are resistant.

• Leaf spot diseases can cause premature death of foliage and reduce plant vigor.

Flowers

• Most bedding plants, summer-flowering bulbs and annual flower seeds can be planted after danger of frost. This happens around mid-April in most of Oklahoma. Hold off mulching these crops until spring rains subside and soil temperatures warm up. Warm-season annuals should not be planted until soil temperatures are in the low 60s.

• Harden off transplants outside in partial protection from sun and wind prior to planting.

• Let spring -flowering bulb foliage remain as long as possible before removing it.

Vegetables

• Wait a little longer for it to warm up before planting cucurbit crops and okra.

• Plant vegetable crops in successive plantings to ensure a steady supply of produce, rather than harvesting all at once.

• Cover cucurbit crops with a floating row cover to keep out insect pests. Remove during bloom time.

• Watch for cutworm damage and add flea beetle scouting to your list of activities in the vegetable garden.

Landscape 

• Hummingbirds arrive in Oklahoma in early April. Get your bird feeders ready using 1 part sugar to 4 parts water. Do not use red food coloring.

• Keep the bird feeder filled during the summer and help control insects at the same time.

• Lace bugs, aphids, spider mites, bagworms, etc. can start popping up in the landscape and garden later this month. Keep a close eye on all plants and use mechanical, cultural and biological control options first.

• Be alert for insect pests and predators. Some pests can be hand-picked without using a pesticide. Do not spray if predators, such as lady beetles, are present. Spray only when there are too few predators to be effective.

Lawn

• Warm-season grass lawns can be established beginning in late April from sprigs, plugs or sod.

• Fertilizer programs can begin for warm-season grasses in April. The following recommendations are to achieve optimum performance and appearance of commonly grown species in Oklahoma.

• Zoysiagrass: 3 pounds nitrogen per 1,000 square feet a year
• Buffalograss: 2-3 pounds nitrogen per 1,000 square feet a year
• Bermudagrass: 4-6 pounds nitrogen per 1,000 square feet a year

When using quick-release forms of fertilizer, use 1 pound of actual nitrogen per 1,000 square feet per application; water in nitrate fertilizers.

• Mowing of warm-season lawns can begin now. Cutting height for bermudagrass and zoysiagrass should be 1 to 1½ inches high, and buffalograss 1½ to 3 inches high.

• Damage from Spring Dead Spot Disease (SDS) becomes visible in bermudagrass. Perform practices that promote grass recovery. Do not spray fungicides at this time for SDS control.

• Grub damage can be visible in lawns at this time. Check for the presence of grubs before applying any insecticide treatments. Apply appropriate soil insecticide if white grubs are a problem. Water product into soil.