Want to grow a green thumb? Follow these guidelines when planting gardens in Texas.

Great gardens operate like clockwork, and that clock has just started ticking. Vegetable gardening season is at hand. I’ll lay out the road map if you’ll just follow these guidelines.

Picking the Site …

Full sun is a requirement, at least for flowering and fruiting vegetables. Leaf and root crops can handle partial shade (morning sun, afternoon shade), but full sun would still be better.

Good drainage is essential. You can always add water to garden soil. It’s much harder to remove it when a soil is waterlogged in a season of ongoing rains (remember those?). Choose a location that drains well.

To improve drainage, a raised-bed garden is always better. If you can elevate the planting area by at least 3 or 4 inches you’ll see a noticeable difference in your crops’ performances.

Good air circulation makes for healthier plants. Diseases are more common in damp, still conditions. Avoid planting sites where buildings, fences and tall shrubs block movement of air.

Preparing the Soil …

Your garden’s soil is like the foundation of your home. If it’s not prepared carefully, nothing good will come from the effort. Vegetables need a minimum of 12 to 15 inches of good garden soil. If you’re establishing your plot on a high spot where bedrock is close to the surface you’ll want to bring in a load of sandy loam topsoil. Insist that it be free of nutsedge (“nutgrass”) and refuse to pay for it if it is not.

There aren’t many absolutes when it comes to gardening, but here’s one: organic matter will improve any type of soil. No matter where you live on the face of the earth, organic matter will make your soil better.

“Organic matter” comes in many forms, including compost, peat moss, rotted manure, finely ground bark mulch and cotton bur compost. It’s best to use a combination of several types for long-term improvement.

The organic matter will loosen tight clay soils and it will help sandy soils retain moisture and nutrition. If you’re working with a clay soil, include 1 inch of expanded shale with 4 or 5 inches of organic matter. With sands, just use that amount of organic matter. Replenish it annually with 2 or 3 inches of additional organic matter. Rototill to 12 inches.

Planning Your Plantings …

Please pay close attention to this part of the story. It’s where many Texas gardeners make their mistakes, especially those who have moved here from other parts of America where planting dates are quite different from ours.

Timing is everything when it comes to vegetable gardening. For each crop that you grow you have a 3- or 4-week window for planting. Plant them earlier and it will be too cool, both in air and soil temperatures. Plant them later and hot weather will ruin the quality of their produce.

The average date of the last killing frost in the Fort Worth/Dallas Metroplex is around March 20. Planting dates are all figured using that as the basis. If you are reading this more than a couple of counties removed from FWD you’ll need to make adjustments according to the average last freeze date for your own county.

Follow these planting guides …

▪ 8 weeks prior to the last killing frost: onions, English peas and the perennial vegetable asparagus.

▪ 4 to 6 weeks ahead of the last killing frost date: Irish potatoes, cabbage, broccoli, cauliflower, Brussels sprouts, kohlrabi and rutabagas.

▪ 2 to 4 weeks ahead of the last freeze date: spinach, leaf lettuce, radishes, beets, Swiss chard, carrots and turnips.

▪ At or 2 weeks after the last killing frost date: tomatoes, peppers, beans, squash, cucumbers, corn and melons.

▪ 2 to 4 weeks after the average date of the last killing freeze: sweet potatoes, okra, southern peas and eggplant.

Trying to rush the season by planting seeds or transplants way ahead of schedule risks losing the crops to cold weather or having them stalled by poor growing conditions. The risks are usually not worth it.

Choosing the Varieties …

Texas-based gardening references will cite the best vegetable varieties for our state. Texas A&M University has good information through its horticulture department, as will other southern Land Grant (agricultural) universities. Claims of national mail order catalogs may not prove too reliable under Texas’ unusual weather conditions.

I generally suggest that Texas gardeners beware of old, inbred “heirloom” varieties. There are often extravagant claims made for these crops, but unless you have a specific reason for growing an old vegetable variety, you’ll generally find that hybrids produced by skilled plant breeders will give much greater yields for the same amount of space and effort. They have been bred for superior resistance to diseases, better flavor, heavier production in shorter time and more “hybrid vigor” overall. Seeds may cost a few cents more, but you’ll get dollars of produce more in return.

You can hear Neil Sperry on KLIF 570AM on Saturday afternoons 1-3 p.m. and on WBAP 820AM Sunday mornings 8-10 a.m. Join him at www.neilsperry.com and follow him on Facebook.