How Can You Protect Tomatoes When Planting Early in the Spring?

Dr. Joe Masabni, Assistant Professor & Vegetable Specialist, Texas A&M AgriLife Extension

How soon can I plant my tomatoes? That's a question on my mind every year. With the winter season towards its end and warm days more and more common, every gardener starts itching to plant his vegetable garden, primarily the king of them all, the mighty tomato.

There's a reason every gardener wishes to plant tomatoes as early as possible, and not just for the need to garden. And the reason is that in most areas of Texas, tomato plants stop setting fruit by early July so we need to maximize our harvest season by first of July. So, the earlier in, the earlier we can harvest before July 1st.

Tomato plants stop setting fruit by July 1st because night temperatures by then is in the mid-70s with about saturated relative humidity. Both those conditions cause the pollen grains of the tomato flower to burst, thus no pollination occurring. So how soon can we plant tomatoes outside and what can we do to win the race game?

In Texas counties east of I-35, the average date of last spring frost is March 1st in the north between Dallas and Houston, February 14th from Houston to Corpus Christi, January 30th from Corpus Christi to McAllen, and no frost normally occurring in the Harlingen area. Of course, these are average frost free dates and growers are reminded to check their local county historical weather data.

With these dates in mind, our goal is to plant as close to the last spring frost date as possible. If we take the March 1st date for the College Station area, then we have 4 months of time before last tomato harvest. But the 4 months are harvest months, we must account for plant growth and development before the fist harvest, which is usually in late April or early June. Basically, we have 1-1.5 months of tomato harvest before July 1st.

So, how can we extend the tomato harvest? We can if we consider cultural methods to plant earlier than the last spring frost date.

Two tools available to the homeowner are hotkaps and pre-punched plastic tunnels. Hotkaps are waxed paper that goes over the small transplant with its edge buried in the soil to hold it down. The Hotkap ( is advertised as extending the growing season by 2-4 weeks. It is a single use item and the hotkaps are sold in quantities.

Hotkap protector
Hotkap protectors

I have used them both in 2010 and 2011 and was pleased with their performance in terms of improved growth with Hotkaps rather than without them.

The pre-punched plastic and the wire hoops used to create a mini-tunnel and an air pocket about 1-1.5 ft over the tomato plants resulted in bigger plants compared to the Hotkaps. The plastic is available on-line from many sources and are usually called 'low tunnels', or 'hoop supported row covers'.

Plastic tunnel
Plastic tunnel

The plastic can be used for multiple seasons if care is given in removal and storage.

Finally, the easiest cultural tool in my opinion is to plant a large plant early in the season. Larger plants can tolerate cold weather and can grow much more rapidly than smaller plants when the weather warms up. The photos below show the before and after images of a large tomato plant buried horizontally except for about 6" of the tip above ground. The leaves will compost, the stems will develop many roots, and the tomato will grow into a large plant in no time.

Large plant, before
Large plant, before
Large plant, after
Large plant, after

So, if you get the desire to plant tomatoes outside in mid February instead of March 1st, make sure you get the biggest tomato plant, bury most of it horizontally, and cover it with a Hotkap or with a small plastic tunnel. With proper fertilization and a little luck, you will enjoy a bountiful harvest.

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