Crop Rotation and Cover Crops

Why it matters

Crops in the same family share the same diseases and pests, and many soil-borne disease organisms live in the soil for years. Rotating families to a new bed each year breaks that cycle and balances what each crop takes out of the soil. Cover crops between seasons keep Texas soil from baking, washing away or filling with weeds, and legumes add nitrogen for free.

Step by step

1. Learn the main families Nightshades (tomato, pepper, eggplant, potato), gourds (squash, cucumber, melons), beans and peas, mustards (broccoli, cabbage, collards, kale, turnips, radish), onions, beets/spinach/chard, carrots, lettuce, corn, sweet potato and okra.
2. Split the garden into four beds or zones Give each major family its own bed this year: nightshades, gourds, beans/peas and mustards.
3. Shift every family one bed each year That way no family returns to the same spot for 3 to 4 years. Fit small families like onions and carrots into any gap.
4. Follow a crop with something unrelated AgriLife's example: follow early beans with beets, bush squash or bell peppers.
5. Keep a simple map Write down what grew in each bed each season so you can rotate correctly next year.
6. Plant a cover crop in empty beds Sow cowpeas, buckwheat or sorghum-sudangrass in summer gaps and cereal rye, oats, crimson clover or hairy vetch in fall.
7. Turn it under before it seeds Cut or turn cover crops under about two weeks before planting (2 to 3 weeks for cereal rye) and never let buckwheat or hairy vetch go to seed.

Key facts

• Iowa State Extension recommends keeping a family out of the same spot for 3 to 4 years, or 5+ if possible.
• Gourd-family crops use a lot of nitrogen; beans add nitrogen; onion-family crops use more potassium.
• Summer cover crops like buckwheat, cowpeas and sorghum-sudangrass are short-term covers of about 45 to 60 days and die with frost.
• Cereal rye survives winter and releases compounds that can suppress seed germination, so end it 2 to 3 weeks before planting.
• Home garden cover crops typically need about 1 to 3 pounds of seed per 1,000 square feet depending on the mix (UGA).
• Buy the right inoculant for legume cover crops so they can fix nitrogen.
• Weeds and cover crops belong to plant families too, so count them in your rotation (a mustard cover crop is a mustard).

Texas notes

• AgriLife row-crop research says plant fall cover crops in early October; the window runs to mid-November but every week of delay cuts spring growth.
• Common vetch and berseem clover have performed poorly in eastern and central Texas; crimson clover, cereal rye, oats, hairy vetch and winter peas did better.
• Cowpeas also help knock down root-knot nematodes, taking about 2 months to bring a population under control.
• AgriLife warns not to plant tomatoes after okra or cotton because they build up root-knot nematodes.
• PLANTanswers advises turning cereal rye under in March and letting it decompose before spring planting.