Tom Longbrake, Extension Horticulturist (retired)
Texas Agricultural Extension Service
Yellow, white and red/purple onions grow very well in Texas home gardens. They grow best in full sunlight and well drained soils.
Soil Preparation
Before seeding or transplanting, work the soil 8-10 inches deep. Break up the clods and rake the soil smooth. Remove all rocks and trash. Work the garden soil only when it is dry enough not to stick to garden tools.
Fertilizing
Onions grow best when the garden soil is fertilized right. Spread 2-3 pounds of a fertilizer such as 10-10-10 over a 100 square-foot area. Measure and spread the fertilizer, then mix it with the top 3-4 inches of soil.
Varieties
| Yellow | White | Red/Purple |
|---|---|---|
| Excel | Eclipse | Burgundy |
| Granex | Majesty | Tropicana |
| Grano 502 | White Grano | Red Grano |
| For green onions: Evergreen Bunching, Crystal Wax | ||
Planting
Onions are a cool season crop and can stand temperatures well below freezing. They may be planted from seed, from small bulbs called sets or from transplants. Seeding is cheapest but takes longer before onions are ready. If you use sets or transplants, plant them 3/4 inch deep and 3 inches apart. Do not transplant onions more than one inch deep. See figure 1.
When seeding onions for bulbs, plant them 1/4 inch deep during October through December. Place seeds 1 inch apart. When the plants are about 6 inches high, thin them to one plant every 2-3 inches. Eat the extra plants as green onions.
Watering
Watering once a week usually is enough. But you may need to water more often during dry, windy weather. Water slowly and deeply to help grow strong, healthy roots.
Care During the Season
Weeds are easy to pull or cut when they are 3-4 inches high. Do not let weeds or grass get large as they steal nutrients from the onions. When hoeing weeds and grass do not chop too deeply. You may be cutting onion roots. Always hand pull weeds when possible.
When onion plants have 5-6 leaves, apply fertilizer again to help grow larger plants and bigger bulbs. Each leaf forms a ring in the onion bulb. More leaves mean more rings and larger onion bulbs. Use about 1.2 cup of fertilizer for each 10 feet of onion row. Scatter the fertilizer evenly between the rows. Water after adding the fertilizer. See figure 2.
Insects and Diseases
Onions do not have many insect problems. But thrips, which are very tiny insects, may be found between the center leaves. Diseases may be a problem on onions. Brown leaftips or brown spots on the middle and lower parts of leaves may be caused by plant diseases. Ask your county Extension agent what to use to control insects and diseases. Follow directions on the container.
Harvesting
Onions seeded in October/December or transplants planted in January/February should produce bulbs in May/July.
Onions may be picked as green onions from t he time they are pencil size until they begin to form bulbs. For dry bulb onions, let plants grow larger. Onions are ready when the main stem begins to get weak and fall. See figure 3. Pull the plants out of the soil. Let them lay in the garden for 1-2 days to dry. Then remove the tops and roots and let them keep drying in baskets or boxes.
Serving
Green onions may be eaten fresh, or can be chopped and added to salads. Bulb onions may be sliced and used on sandwiches, or dipped in batter and fried as onion rings. Onions are a source of Vitamins A and C, but are used mostly as a flavoring in other food dishes.
Storing
Store onions in a crisper, or in a dry, airy place such as a wire net in the garage or carport.
