How often should I refresh garden soil?
Written by
Nguyen Minh
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Soil health in a square foot garden depends on the addition of materials to improve it, not the complete change of content. I have maintained a productive garden bed for more than 8 years by continually adding compost each year and utilizing a crop rotation system. One client's grid produced 15 lbs of kale each year for seven years without the soil ever being changed, which is simply a demonstration that well-thought-out additions will maintain soil fertility.
Compost Layering
- Apply 1.5 inches of compost each spring and fall
- Mix 3-5 compost sources (manure, leaf mold, mushroom)
- Avoid fresh manure, cure 6 months to prevent root burn
Crop Rotation
- Shift plant families yearly (brassicas → legumes → nightshades)
- Prevents nutrient mining (e.g., tomatoes deplete phosphorus)
- Breaks pest/disease cycles naturally
Soil Testing
- Test pH/nutrients every October
- Use vinegar-baking soda test for quick pH checks
- Add worm castings if nitrogen dips below 2%
To maintain soil structure, do not till. In my no-dig beds, I have 8 species of earthworms that are aerating in soils deeper than any mechanical tool can penetrate. If an area is compacted, simply insert a broad fork, being careful to rock it back and forth rather than flipping over soil layers. This is to keep mycorrhizal networks that aid nutrient uptake.
Organically rebalance nutrients. For example, a client's beans started to yellow; we added 3 cups per square of alfalfa meal, and nitrogen levels rebounded in about 10 days. Bone meal provided phosphorus more quickly than rock phosphate. Always retest the soil or plant as a source of rebalanced nutrients 3 weeks after any amendments to verify nutrient levels are corrected.
Read the full article: Ultimate Square Foot Gardening Guide: Maximize Your Harvest
