By Erin Marissa Russell
Are you curious about using garden lime for tomatoes? Want to know how to do it, as well as the benefits and potential problems of tomatoes and garden lime? Just keep reading. We’ve prepared this article to guide you every step of the way.
What Is Garden Lime?
Garden lime is calcium carbonate, and it’s used to raise the pH level of soil as well as to add calcium to the soil for plants. You should know that garden lime is sometimes called agricultural lime. The names garden lime and agricultural lime both refer to the same product.
Dolomitic lime, or dolomite lime, is a different substance you may hear about that also raises soil pH. Dolomite lime contains calcium carbonate as well as magnesium carbonate. In addition to boosting calcium, dolomite lime supplies magnesium to your soil at the same time.
Quick lime, also called burnt lime, is another product that has a similar sounding name, but quick lime is not recommended for use in the garden.
Garden lime is sold in a few different forms: granular, hydrated, pelletized, and pulverized. Some of these preparations are more expensive than others. For example, pelletized lime is more expensive than granular lime. However, pelletized lime does not work any faster than granular lime, so it’s not really worth the extra cost.
Pulverized lime has the smallest granules, which means the lime will absorb more quickly into the soil. Hydrated lime is also absorbed quickly, but it can be harder to control the application than with other forms of lime.
The lineup of options can seem overwhelming, but all you really need to consider is how much you want to spend on garden lime and how quickly you need your lime to work.
Lime is used to prevent blossom end rot in tomatoes. When the soil doesn’t have enough calcium, especially if the weather has been dry, then wet, then dry, then wet, blossom end rot can take hold. You can prevent this risk by adding garden lime to your soil, which will raise its pH level while also adding calcium.
Blossom end rot won’t prevent tomatoes from ripening and maturing. You’ll notice that as a tomato with blossom end rot grows, it will get small brown or tan spots on the end of the tomato that had the blossom. The spots start out so small that you may not notice them, but they eventually expand to up to two inches wide. Then the blossom end of the tomato starts to decay, leaving the rest of the tomato edible, although not pretty to look at.
Lime is also used to bring the pH level of the soil up to an appropriate level for growing tomatoes. The ideal soil pH for growing tomatoes is between 6.5 and 6.7. If your soil has a lower pH level and you want to grow tomatoes, garden lime can help them thrive. Not sure what the pH level of your soil is? Find out in our article How to Test pH in Your Soil.
One avenue for soil testing is to connect with your local Extension office, as these offices offer soil testing services. You can also order soil testing kits at hardware stores or online if you’d prefer to test the soil yourself. If you find that you need to increase the calcium in your soil without changing its pH level, consider using gypsum instead of garden lime.
- The main benefit of lime, and one major reason people use it in the garden and especially with tomatoes, is that it raises the soil pH level to create the slightly acidic environment where tomatoes flourish.
- Lime also adds nutrients to the soil, such as the calcium and magnesium tomato plants need to thrive. Calcium is vital in the creation of plant cell walls, development of the primary root system, and transportation of nutrients.
- Lime makes it possible for water to better penetrate the soil, where it is accessible to your plants.
- When your soil has the appropriate pH for growing tomatoes after you’ve used lime, nutrients like magnesium and phosphorus will be available to your plants.
- Make sure you only use as much garden lime as you need. If your tomato plants get too much lime, they won’t be able to take in the magnesium they need from the soil. Magnesium is necessary for the production of chlorophyll. You can avoid using too much lime by checking the pH level of your garden before you apply lime and only using the amount you need.
If you do get too much lime in your soil, you can correct the pH level with elemental sulfur or ammonium sulfate. It’s best to apply a sulfur treatment in the fall so it can work over the winter, leaving the pH level corrected in the spring.
- Garden lime can be dangerous to humans and animals if consumed. Make sure to dig it 12 inches into the soil so it’s not sitting on the surface where children or pets can get to it.
- Although you will begin seeing the benefits of garden lime in a few months, it takes two or three years for it to completely change the soil. The time it takes for garden lime to work in your soil depends on the type of lime you use, size of the lime particles, the soil’s current pH level, and the type of soil you have. Garden lime takes longer to work in clay soil, so the more clay your soil contains, the longer your soil’s transformation will take.
- Certain plants prefer acidic soil and do not do well when the pH level is raised with lime. These plants include azaleas, blueberry bushes, and rhododendron.
- If you use garden lime to raise the pH level of your soil too quickly, it can have a negative impact on your plants. Plants can be shocked and damaged by too quick a change in pH level. This is why some people use treatments meant to adjust their soil’s pH level in the fall when plants are not growing.
Another alternative is to treat your soil with half of the garden lime in the fall and use the other half in the spring before tomatoes are planted. The cycle of freezing and thawing that occurs over the winter will also help incorporate your garden lime into the soil.
At least two to three months before you plan to plant your tomatoes is the recommended time to apply garden lime. A good guideline for soil amendment is three quarters of a cup of garden lime for each tomato plant.
However, if your soil testing indicates that you need more or less lime than three quarters of a cup per tomato plant, follow that ratio. The amount of lime you should use varies depending on your soil pH level. For a table showing you how much lime to use to adjust soil pH by a certain amount, visit this article on changing pH in soil from the Vegetable Research and Information Center of the University of California at Davis. You can use the listed values as a guide and estimate how much lime to use based on your garden’s soil testing results.
Using a rototiller, rake, or spade, mix the lime into the soil down to a soil depth of 12 inches. Water the soil after you’ve finished mixing in the lime.
While you’re adding garden lime, it’s also a good time to add fertilizer. Use a balanced fertilizer like an 8-8-8, and just like with the lime, use three quarters of a cup per tomato plant.
To fight off garden pests, you can use lime water or a lime slurry. If you apply the lime water or lime slurry as a spray to the plants’ foliage, it will fight pests like aphids, leafminers, and whiteflies. Create the lime slurry by mixing a teaspoon of garden lime into a gallon of water. Continue mixing until the lime has dissolved. Use a spray bottle to apply the lime slurry to your plants, making sure to get the undersides of the leaves where pests can congregate.
Garden lime isn’t the only thing you can use to help your tomatoes stay free of blossom end rot. Wood ash is another soil amendment you can use to raise the pH and add calcium, and at the same time it will add potassium, phosphorus, and magnesium. Plants that have a consistent, slow source of water are less at risk of falling victim to blossom end rot. Using mulch around your tomato plants can also help prevent the disease.
You can also prevent blossom end rot and other types of disease by following good watering practices, which means watering in the morning and aiming the stream at the roots of your plants, not splashing on their foliage, which leaves behind the excess moisture that puts plants at risk.