Neil Sperry: Time to think about your North Texas vegetable garden. Here’s when to plant

Knowing when to do things in your vegetable garden is just as important as knowing what to do. I’m a veteran of 52 of these battles with the Texas weather, soils and pests, and I can tell you that the gardeners who succeed do so by hitting their timings.

Every last crop that you grow has a specific planting window of two or three weeks. Speaking to the spring garden, if you plant too early (before that window opens) you’re risking losing everything to cold weather. If you plant too late (after the prime time) your crops may fade in the heat or they may develop bitter flavor. Remember the windows and if somehow you miss one for a few of your crops, don’t press the issue. Move on to others.

We need a reference point so that you can determine the garden windows for your own part of Texas. The only logical one is the average date of the last killing freeze. For most parts of the Metroplex that’s going be be around March 17-20. However, this paper covers a big part of Texas, and it’s critical that you know your own specific date for your city or county. Texas-based reference books should have maps showing those dates. So will online information from the Texas AgriLife Extension Service of Texas A&M. But easiest of all, you can Google that information or simply ask your electronic assistant, “What is the average last killing freeze date for __ County, Texas?”

Keep that date in your memory. Write it down in your gardening journal. Tattoo it to your forearm.

First assignment: get the soil ready …

Do this now. Start with an appropriate site in full sun and near an available source of irrigation water.

Remove all existing vegetation if it’s a new plot. Weedkillers won’t work in these cool temperatures, so you’ll have to use a nursery spade to remove existing sod and perennial grasses.

Rototill to a depth of 10-12 inches. That’s hard work that is best accomplished with a rear-tine rototiller. They do the best job of pulverizing and mixing the soil.

Rake out all debris and roots, then incorporate 5 or 6 inches of equal amounts of well-rotted compost, manure, finely ground pine bark and sphagnum peat moss. If you’re amending a clay soil, include 1 inch of expanded shale. Rototill again to 12 inches to blend it all together and rake it to a smooth top. That will give you a raised planting bed that will ensure good drainage.

To be planted 6-8 weeks before the last killing freeze date…

These are the vegetables that need cool weather to grow and be productive. They must be planted early or they will run into heat delays at the tail end of their season. In Tarrant County this will mean they should be planted the last two weeks of January (possibly a week or two earlier in the urban heat pocket inside Loop 820 of Fort Worth where temperatures stay slightly warmer).

At the top of this list would be onions such as the long-popular Texas Supersweet (1015-Y) developed by Texas A&M. Onion transplants are planted shallow in the soil. Veteran growers will tell you to aim for 15% of the transplants to fall over when you water them the first time. At that point you will simply replant those and move on.

Asparagus is the other vegetable that gets planted quite early. It can actually be planted anytime in January. Buy plump 2-year-old roots at a local nursery or feed store and plant them where they can grow undisturbed for many years. The north side of your garden would be best, so the tall plants won’t shade and crowd into the rest of your plantings on down the road. You won’t get any harvest for the first year and limited production the second year.

To be planted four weeks before the last killing freeze date …

This is a larger list and it includes several very popular vegetables. These would be planted around mid- to late February.

Irish potatoes fall here. Buy certified seed potatoes from a nursery or farm store. Cut them into pieces containing three or four “eyes” (buds) each. Let the pieces dry on a sheet of newspaper for 2 or 3 days prior to planting. Plant them 5 or 6 inches deep in very loose, highly organic soil. It’s a good idea not to fill the planting trenches in completely until the seed pieces start growing. You can then pull loose soil up around their stems as they develop.

The other major group of vegetables that get planted in mid-February is the Cole crops (as in Cole slaw), including cabbage, broccoli, cauliflower, Brussels sprouts and other lesser types. These are best planted as potted transplants as opposed to being planted from seeds.

To be planted 2-4 weeks before the last killing freeze date …

And finally (for now), we have leafy and root vegetables that should be planted two to four weeks before the last killing freeze date. For the most part, these are somewhat “lesser” vegetables unless your favorites happen to fall on this list: carrots, radishes, beets, spinach, lettuce and a handful of others.

That takes us up to the “warm-season” vegetables (the “Biggies”), and that’s where I’m going to pick up next week. We grow some of those crops as potted transplants, so their indoor planting dates fall back into late January and February. Hang onto this story and combine it with next week’s and it should be a good start to a useful gardening journal.

This story was originally published January 6, 2023 at 6:00 AM.