How to prepare garden soil for growing tomatoes

This post was written by Leslie J. Shearer. Homeware Huntress may collect a share from publishing posts by other authors.

Tomatoes can only grow healthily in nutritious soil, so some types of soil are not a good choice for gardening. If you’re planning to have tomato plants in your garden, here are some tips for preparing the soil correctly…

Textures and Types

Loam soil or sandy loam soil are both perfect choices for tomato growing. However, except for heavy clay, tomato plants can still grow in nearly all types of soil.

If there’s too much clay in your soil, you need to improve its texture. Texture improvement requires you to till your soil, then add sawdust, peat moss, sand and other amendments before you can grow tomatoes. The result is your soil becomes quite well-drained and loose.

Dry soil doesn’t work well for tomatoes. Yet, you should not grow these plants in the soil that is too wet and waterlogged or soil where standing water clutters after it rains.

Soil testing

It’s also necessary to give your soil a test on the proportion of nutrients and chemicals it contains. This test is simple and helps you figure out the way to amend your soil. You can do a soil test by yourself by purchasing an affordable soil test kit at garden centres or online.

When you do a soil test, you will also know the pH level of your soil.  A kit for pH testing is simple and good enough to tell you the pH level of a tomato patch. However, if you plan to produce a larger number of tomatoes, you’d better do more tests on different areas of your planting land.

The neutral level of pH stands at 7.0. Lower than that figure, your soil is acidic – and the acidity degree increases when pH level decreases. In contrast, a level of 7.0 plus means your soil is alkaline – the alkali degree increases when pH level increases.

The perfect pH level for the best growth of your tomatoes hovers around 6.0 to 7.0, which indicates that the soil is slightly acidic. And the optimum level is from 6.5 to 7.0. You should give your soil proper amendments if its pH doesn’t stay within this range.

To reduce the pH level, add sulphur to your soil.

To make the pH level higher, add lime to your soil.

All in all, an appropriate level of pH plays an important role in soil preparation for growing tomatoes.

Garden Soil Improvement

In case your soil is too acid (or its pH is extremely low), you need to provide your soil with lime in order to bring back its pH level into the appropriate range. Often gardeners have alkaline soils (or high pH level), and they need to work sulphur into their soils to reduce pH level.

You can add sulphur or lime into your soil whenever the ground is not frozen. Even so, you should best do it in Autumn since this season is convenient enough to make sure slow-acting lime has time for taking effect.

Based on what the report on your soil test says, you should consult your local garden centre to know the right amount of sulphur or lime to apply.


Air is vital for plants, just like the way it is for humans. A plant needs air for photosynthesis not only above but also under ground. Air staying in the soil means there is atmospheric nitrogen available for the plants to use once it’s converted. Also, oxygen in the soil is essential for soil organisms – those beneficial beings for your plants – to survive.

If your soil is good, that means its particles are provided with appropriate space to hold the air used by your plants. For heavy and silty clay soils, their small particles stand close to each other, thus making these soil types too dense to contain air.

Conversely, sandy soils have too big particles, and the space between these particles are too large. As a result, the amount of air that sandy soils give is excessively high and makes organic matter decompose rapidly.

You can apply compost or other organic matter to your soil to strike the balance of its air supply. In fact, the perfect air proportion is around 25%. You should also avoid using heavy equipment or stepping in the garden beds because such doing can compact your soil. Try not to work the soil when it is extremely wet.


If your soil is moderately fertile and contains much organic matter, your tomato plants will grow well. During the time for soil preparation, you can add compost or some all-purpose fertiliser with phosphorous and potassium content to boost your soil’s fertility.

Once you’ve well tilled your soil and made it loose, then make a furrow or a trend at a depth of 6 to 8 inches to form a tomato row. You should also add a slightly thin band of chemical or organic fertiliser at the furrow’s bottom.

The type of fertiliser you can apply is 5-10-10, whose numbers respectively refer to the by-weight percentages of N-nitrogen, P-phosphorous, and K-potassium in the fertiliser bag. The order N-P-K is always fixed.

You can also try another way: putting a band of compost, rotted leaves or dried animal manure deeper down into the furrow. Or, you can combine both ways to help your tomatoes grow fast and healthy.

Whichever way you choose, you should use a soil amount of 2-3 inches thick to fully cover the fertiliser. If the stems or roots of your transplants are directly exposed to the fertiliser, this will do harm to your plants since their moisture can be drawn by the salts the fertiliser contains.

On the other hand, if the fertiliser stays deep underneath your plants, their roots will over time grow to absorb its nutrients.

After you’ve covered the fertiliser, the final step is to transplant your tomatoes into the furrow at a depth of three to four inches.


An organic mulch such as hay, grass cuttings, straw or shredded bark covers your soil and shields it from extreme cold and heat. Mulches save your plants from losing water through evaporation and hinder weed growth. They slowly decompose and fertilize your soil by adding organic matter.

Similar to organic mulches, inorganic mulches such as pebbles, black plastic, gravel or landscape fabrics help prevent your plants from evaporating rapidly and stamp down weeds. However, one thing inorganic mulches differ from organic ones is you don’t have to replace them every year, and they won’t attract rodents or insects.

Nevertheless, since inorganic mulches do not decompose and add organic matter to your soil, they can’t improve the structure of your soil and make it more nutritious. So, if you want to enhance the soil structure, you’d better go for a high-quality, seed-free and clean garden mulch.

About the author:

Leslie J. Shearer is the founder and owner of the blog Gardening is her passion and she has a deep relationship with nature. Growing plants and digging deep to germinate flowers and vegetables brings positivity in her life.

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