Is your garden struggling to thrive? The problem might be your soil! Here are some of the most common soil nutrient deficiencies—and how to fix them!
For organic gardeners, improving soil is a never-ending task. Plants soak up nutrients as they grow, and it’s up to you to replenish them to keep your soil healthy.
To keep your soil in top shape, mix in plenty of organic matter and compost, rotate your crops, and watch closely for signs of missing nutrients.
5 Soil Nutrient Deficiencies (and How to Fix Them)
Ever wonder why your plants aren’t doing well?
- Why are your tomato leaves turning yellow—or not flowering at all?
- Why do your corn stalks have a strange purple tint?
- Why are fruits dropping before they’re ripe?
Here are the most common soil nutrient shortages—and how to fix them for a bigger, better harvest!
Nitrogen Deficiency
Many favorite crops are heavy nitrogen feeders. Signs your soil needs more nitrogen:
- Yellowing lower leaves
- Slow, stunted growth
- Wilting even with normal weather
How to fix it:
- Mix in aged poultry manure or blood meal.
- Plant legume cover crops in winter to boost nitrogen.
- Add compost or organic matter right before spring planting.
Calcium Deficiency
Calcium shortages cause big problems, especially for fruiting plants. Look for:
- Blossom end rot (in tomatoes, peppers, squash)
- Yellow, curling leaves
- Blackened growing tips
- Stunted growth
How to fix it:
- Work bone meal or lime into the soil.
- Crush and bury clean eggshells.
- For a quick fix, spray leaves with calcium solution.
Magnesium Deficiency
Magnesium helps plants produce chlorophyll. Without it, growth suffers. Signs include:
- Yellowing leaves (older ones first, veins stay green)
- Purple, brown, or red leaf tints
- Small, tough fruits with poor color
How to fix it:
- Enrich soil with organic compost.
- Use Epsom salts: Add a few tablespoons at planting or mix 2 tbsp per gallon of water.
Potassium Deficiency
Potassium boosts fruit production and disease resistance. Watch for:
- Scorched, curled, or deformed leaves
- Weak stems
- Poor root growth
- Early fruit drop
How to fix it:
- Bury a banana peel when planting.
- Lightly apply wood ash (too much can burn plants).
- Try greensand for extra potassium.
Phosphorus Deficiency
Purple tomato leaves? That’s a phosphorus issue! It helps plants use other nutrients and is key in commercial fertilizers. Signs:
- Small, thin-stemmed plants
- Fewer flowers/fruits
- Purple leaves
How to fix it:
- Add bone meal or rock phosphate.
- Mix in aged chicken manure.
- For existing plants, spray weekly with fish emulsion.
Quick Soil Deficiency Guide
How to Fix Your Garden’s Soil
If you suspect nutrient shortages, test your soil first (check with your local extension service).
Pro tip: Fix soil in the off-season! Add compost and amendments early to prevent problems later.
Also, practice crop rotation and companion planting to avoid draining the same nutrients year after year.