Is your garden not growing like it should be? Maybe it’s your soil! Here are some of the most common soil nutrient deficiencies- and how to fix them!

Soil improvement is a never ending job for the organic gardener. As they grow, plants use up nutrients in the soil and it is the gardener’s job to replace them in order to maintain the overall health of the soil.

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It is important to replenish the soil by digging in lots of organic matter and compost, practicing crop rotations, and by carefully observing what nutrients the soil is lacking.


5 soil nutrient deficiencies and how to fix them


5 Most Common Soil Nutrient Deficiencies and How to Fix Them

What do you do when your beautiful plants start to go down hill?

What does it mean when your tomato plant’s leaves turn yellow or don’t produce any flowers or fruits?

What does it mean when your corn stalks take on a purplish color?

What does it mean when ripening fruits drop too early?

Here are some of the most common and most important soil nutrient deficiencies and how to fix them so that you can have a bigger, better harvest!


Nitrogen Deficiency:

Many of your most popular crops are heavy feeders that need a lot of nitrogen. Here are the sign of nitrogen deficiency in the soil:

  • Yellowing on the lower leaves of the plan
  • Stunted growth
  • Wilting under normal weather conditions

So how do you fix it? 

Nitrogen deficiency can be cured by amending the soil with aged poultry manure or blood meal

Using a legume cover crop in the winter can help to fix nitrogen in the soil. 

Adding organic matter and compost to the soil directly before planting the spring can give your soil- and your crops- a boost. 


Calcium Deficiency 

Calcium deficiency can cause lots of problems in the garden- especially in your flowering and fruiting plants. Here’s what to look for:

  • Blossom end rot in flowering/fruiting crops such as tomatoes, peppers, and squash
  • Yellow, curling leaves
  • Blackened growing tips
  • Stunted growth

How do you fix it?

Adding bone meal or lime is great for adding calcium to the soil. You can also clean and crush egg shells to dig into your soil.

For a quick fix for your plants, use a foliage calcium spray. 


2 tomatoes with blossom end rot due to calcium deficiency in the soil


Magnesium Deficiency 

Magnesium is directly tied to chlorophyll in plants. If your soil is magnesium deficient there will also be a shortage of chlorophyll which can cause poor or stunted growth. Here’s what to look for when identifying magnesium deficiency in the soil:

  • Yellowing or loss of color in leaves – especially on the older, lower leaves. Veins often stay green.
  • Purple, brown, or red coloring may be seen on the leaves
  • Stunted growth- smaller, woodier fruits with poor coloring

How do you fix magnesium deficiency in the organic garden?

Amending the soil with rich, organic compost can replenish this nutrient. 

You can also use Epsom Salts. Add a few tablespoons of Epsom salt to the hole at planting time or mix 2T of salt with 1 gallon of water to feed your plants. 


Potassium Deficiency 

Potassium is an essential nutrient for fruit production and it helps plants fight disease. Here’s how to identify potassium deficiency:

  • Deformed or stunted leaves; scorched or dead looking edges
  • Weak stems in plants
  • Poorly developed roots
  • Fruits dropping prematurely from the plant

Here’s how to fix potassium issues in your organic garden:

Use a banana peel! Plant a banana peel in the hole at planting time to help combat potassium deficiency. 

You can also use wood ash, but use it sparingly so that you don’t burn your plants. 

Greensand can also help add potassium to the soil. 


nutrient deficiency in tomato seedlings with veining and yellowing leaves


Phosphorous Deficiency 

Have you ever noticed that the leaves of your tomato plants turned purple? That’s a phosphorous deficiency! Phosphorus is very important because it helps the plant convert and use other nutrients. It’s one of the 3 main nutrients in commercial fertilizers.

Here are the most common signs of this deficiency are:

  • Small, stunted plants with thin stems
  • Reduced flowers and fruit production
  • Purple hue to the leaves

How do you fix it?

Bone meal and rock phosphate are great options for adding phosphorus to the soil.

Amending your soil with aged chicken manure is also a great option. 

For plants that are already growing, try spraying the plants with fish emulsion weekly to help them grow better and recover. 


Here’s a quick-glance chart to help you diagnose your own garden and it’s soil nutrient deficiencies:


Soil Deficiencies Chart


How to Fix Soil Nutrient Deficiencies in Your Garden

If you think you have some issues with deficiencies in your garden, it’s always best to get a soil test so that you can be absolutely sure what you are dealing with. 

Check with your local extension service to resources on getting your soil tested. 


I also recommend using the off season to fix any soil issues. That way you can prevent problems in your crops instead of dealing with them all season long. 

Use this time to add compost to your soil and any other amendments you may need.

Here’s a list of 8 ways to amend your soil for FREE– so you can have the best garden without spending a ton of money, 


You should also pay attention to things like crop rotation and companion planting. That way you can be sure you aren’t planting lots of heavy feeders in the same area or in the same garden bed year after year. 


What have you used to cure nutrient deficiencies in your garden?