Tomato tips

Tips for tomato growers 

Ward Upham, K-State Department of Horticulture

Transplanting Tomatoes Early

If you would like to have your tomato plants produce earlier in the year, there are certain things to keep in mind. Most people who try to get a jump on the season set their tomatoes out early and hope they do well. However, that is often not a good plan as tomatoes have to have certain requirements before they will grow well.  Those requirements are an acceptable soil temperature for root growth and an acceptable air temperature for both plant growth and fruit set.

Root Growth: Tomatoes need a soil temperature of at least 55 degrees to do well. Plastic mulch is most commonly used to warm the soil. Several days may be needed to raise the soil temperature. Check the soil temperature 2.5 inches deep in the soil at about 11:00 a.m. If that is not possible, check the temperature before leaving for work and again when you return and use the average of the two. It is best to lay a drip irrigation line before installing the plastic to

make watering more convenient. See accompanying article on laying plastic mulch.

Air Temperature: Plants must be protected from frost. Hot caps or water teepees are placed over the young plants to provide protection as well as provide a higher average temperature to encourage growth. Eventually the plants will outgrow the cover and start to develop flowers. But if the temperature goes below 55 degrees at night, tomato flowers may not set. The plant is not hurt, but the blossom will not set fruit, or, if it does set fruit, the fruit is often misshapen.

How early can you transplant? Start with a date about 2 weeks earlier than normal. (Ward Upham

Laying Plastic Mulch

Plastic mulch is sometimes used to start vegetables such as tomatoes and melons earlier than normal.  Commercial growers use a machine to lay the mulch, but home gardeners must do this by hand.  Following are some tips on how this is done.

1. Fertilize according to soil test. You won't be able to add fertilizer after the plastic is down.

2. Work the soil so that the bed can be easily shaped.

3. Use a garden hoe to form a trench along all edges of the plastic. The soil should be pulled to the outside of the bed. The trench should be formed six inches in from the edge of the plastic and extend along both sides and both ends. The trench should be deep and wide enough to bury six inches of plastic.

4. Lay trickle irrigation tube down the center of the bed. This isn't absolutely necessary but it makes it much easier to water. Overhead watering will hit the plastic and roll off.

5. Lay the plastic down and cover the edges with soil. You need to slit the edge of the

plastic where the trickle irrigation tube enters the end of the bed.

6. Plant when the soil temperature reaches the correct temperature for the crop (55 degrees for tomatoes and 60 degrees for melons) at a 2.5-inch depth. Check the temperature at about 11:00 a.m. to get a good average temperature. Check for several days in a row to ensure the temperature is stable.  A hole can be made in the plastic by cutting and "X" in the plastic with a knife or by burning a hole with a hand-held propane torch.  (Ward Upham)