For onions, it’s time to get growing. Here’s your North Texas timeline for success

Spring starts early if you’re an onion. They’re the first vegetables most folks plant into their gardens, and in these parts (Fort Worth and its surrounding areas), late January is prime time. In fact, it’s more than just “prime” time — it’s a critical time, because if you set your onion transplants out too late, they’ll run into hot weather before they have a chance to form nice big bulbs.

Just so you won’t fly off the tracks along the way, let’s outline your steps to onion-growing success.

▪ Full sun. Onions grow best in full sun all day. Anything else is a compromise. At most give them no more than a couple of hours of afternoon shade.

▪ Perfect drainage. Since they’re mainly a root crop, they’re not going to thrive in water-logged soils. Granted we don’t live in swampy country here in North Central Texas, but you never know when we’re going to be blessed with a wet spring. There have been years where our annual quota of rainfall has been met by the end of April. Those years were not good for onions unless gardeners took the necessary precautions.

▪ Raised planting beds. This is the quickest way to improve garden drainage. You either build flattened berms of soil as you prepare for planting, or you use decay-resistant timbers or large river rocks or concrete blocks to build your raised bed. It only takes 4 or 5 inches of elevation to cause incident rainfall to run off instead of super-saturating the ground. It can make a big difference in the success of your crops.

▪ Prepare the soil carefully. You don’t get a second chance until the next crop. Rototill 6 to 8 inches deep as you incorporate several inches of well-rotted compost and manure along with 1 inch of expanded shale into our native black clay topsoil. You want the finished garden soil to be loose enough to rake easily so that you can plant your onion transplants by hand.

▪ Pick your favorite varieties. In North Texas we will need to grow “short day” varieties for best success in early spring. The standard of excellence for the past several decades has been Texas 1015Y. Developed by Texas A&M, it’s known for its great flavor, large size, disease resistance, and high yields. Yellow Granex is another popular short-day onion for our area.

▪ Choose healthy transplants. Nurseries and feed stores have bundled transplants available now. Pick bright green, vigorous looking bundles.

▪ Space plants carefully. Set the transplants 4 inches apart in their rows. (3 inches apart if you intend to thin the plants for use as green onions as they develop.) The rows should be 16 to 20 inches apart to allow ample room for cultivation. Set the transplants shallowly (approximately 1 inch). If the initial planting is done correctly, 15 or 20 percent of the transplants will fall over the first time that you water them. Replant those and your plants will be ready to go.

▪ Irrigate regularly. Onions need water to develop good foliage and bulbs. While we do worry about drainage, we must also be concerned about keeping the plants growing vigorously throughout the spring. Each ring in the onion bulb is associated with a new leaf, so we want as much growth as possible while conditions are favorable. Amount of water depends, of course, on temperature, wind, and sun, but on average, your onions will need 1 inch per week.

▪ Fertilize your plants. Again, your goal is to keep them growing. Depending on where guidance is being given, fertilizer analysis may vary considerably. The general statewide recommendation by Texas A&M calls for application of 10-10-10 fertilizer, 2 to 3 pounds per 100 square feet. Metroplex recommendations, however, suggest less phosphorus (middle number of the analysis) or even all nitrogen such as ammonium sulfate applied to our alkaline black clay gumbo soils. Timing of the feedings should be when the plants reach 6 inches and again when they reach 12 inches in height.

▪ Control weeds regularly. Onions do not compete well with other unwanted plants. You can use a small, well-sharpened hoe to remove seedling weeds carefully, but stay away from the onions’ roots and developing bulbs. Pulling by hand is always the safest way.

▪ Harvest when onions are ready. Bulbs will start to develop by early April. They’ll be ready for harvest when the stems begin to fall over. Carefully dig them out of the soil and lay them on the ground for a couple of days with their foliage shading the bulbs. Trim them to remove most of the tops and place them on newspapers in a well-ventilated garage or porch to dry additionally. Store them in the crisper drawer of your refrigerator. If you don’t have room for that, put them in open -mesh bags or boxes in good ventilation in the coolest room that you have.