Just like other fruits and vegetables, tomato plants need the right amount of nutrients including calcium.
Tomato plants can get too much calcium, but if you know what to look for, you can remedy the problem quickly. The first thing you’ll notice with an too much calcium is a discolored leaf, which usually starts as yellow and eventually turns brown.
But there are other signs as well. Check out the top 3 signs of too much calcium in tomato plants.
3 Signs of Too Much Calcium in Tomato Plants
Some of the signs that your tomato plants have too much calcium include:
1. Discolored Leaves
When tomato plant leaves go from yellow between the veins to a light crunchy brown, it’s a sign that it has too much calcium. The technical name for this is inter-vein chlorosis, and it’s the first sign that something serious is wrong with your tomato plants.
2. The pH Level in Your Soil is Too High or Low
Ideally, the soil that you grow your tomato plants in should have a pH level of between 6.0 and 6.8.
Low pH levels or acidic soils will often need the addition of garden lime or calcium to increase the pH however high pH soils have often had too much garden lime added.
For soils with high pH or too much garden lime, mix through some compost and aged cow manure to help to reduce the pH.
3. The Plants Do Not Thrive
When your tomato plants get too much calcium, they aren’t able to properly absorb the other nutrients you give them.
This puts the balance of nutrients in the plant out of whack, so to speak, which is the same thing as saying the plants are not receiving the nutrients they need to grow and thrive.
What to Do If Your Tomato Plants Have Too Much Calcium
If your tomato plants have too much calcium, here are a few things you can do to remedy the situation:
- Plant products such as Swiss chard and spinach near the tomato plants, which remove some of the excess calcium.
- Water more often to get rid of calcium and salts.
- Add organic matter such as compost, rotted leaves, and aged cow manure.
- Use a compost made out of grass clippings, kitchen scraps, or animal manure.
How Much Calcium to Give to Tomato Plants
For your tomato plants to have the right amount of calcium, you’ll have to first test the soil with a pH meter. If the number is too low, you can start by adding garden lime, which is also called calcium carbonate.
Start by adding 1 pound per square yard of soil, but you can go up to 3.5 pounds per square yard if the calcium level needs to be raised even more. Dig or till it into the top foot of soil and go from there.
The best time to do this is either in the fall or the early part of spring.
If you choose to wait until the spring, you’ll want to use 3/4 cup of lime per plant and work it into the top 8 inches or 1 pound of soil. If you haven’t added lime to your tomato plants for several years, you can increase the amount up to 2 cups of lime.
If you grow your tomato plants in containers, you’ll need to use 1/4 cup of dolomite lime for every 10 quarts of potting soil you’re using. Keep in mind, however, that a calcium deficiency in your tomato plants isn’t always caused by a lack of calcium in the soil.
Different things can change the way tomato plants absorb calcium, including stress, root damage, too much nitrogen, and either too little or too much water.
If you add mulch to the plants while they are damp, it will help keep the moisture level of the soil more consistent. Try to give the plants 1.5 inches of water per week to help them grow the way they’re supposed to, and when you add fertilizer, only add it to the top 8 inches of the soil.
How to Give Tomato Plants the Right Amount of Calcium
There are several ways to give your plants the right amount calcium, and they include the following:
Adding garden lime is the best way to give plants an even amount of calcium. What lime does is add calcium to the soil and makes the soil less acidic.
Lime is easy to find at nursery centers and home-improvement stores, and it is a combination of calcium carbonate and other forms of mined limestone.
2. Dolomite Lime
This is calcium carbonate only and also contains magnesium carbonate. This means you’ll have to first test the magnesium level of your soil and if it’s too high, use another form of calcium besides dolomite lime.
3. Wood Ashes
Always use hardwood ashes and not the softwood type, and keep in mind it will also raise the total pH level of the soil. If your pH level is fine and you don’t want it raised, you can consider other types of wood ashes, such as softwood ashes.
4. Bone Meal
Compared to lime, bone meal is slower to release, high in phosphate, and less soluble. Bulbs and root crops do especially well with bone meal, and if you want to raise the pH level of your soil just a tad, bone meal is the perfect solution.
Also called calcium sulfate, this is a fast-acting calcium supplement and even better, it neither raises nor lowers the pH level of your soil. It makes the perfect calcium supplement when all you need is a little extra calcium and nothing else.
6. Ground Oyster/Clam Shell Flour
This is an effective calcium supplement but it can take several years to have the best effect on your plants. Over time, it can also raise the pH level of the soil.
It is sometimes difficult to tell if tomato plants have too much calcium, but one way to know for sure is their yellowing leaves. Testing the pH level of your soil on a regular basis is a smart thing to do if you want the calcium level to be just right.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.