Fertilizing Tomatoes Tomatoes

How To Fertilize Tomatoes: From Planting To Harvest

Fertilizing your tomato plants is one of the major issues to become a successful gardener. Most garden soil doesn’t contain the required nutrients needed for plant development.

Proper portion of fertilization during cultivation season is necessary not only to get better yield but also to avoid some problems.

Irregular and imbalance fertilization can hamper the plant growth, moreover susceptible to some diseases.

So become a smart gardener you must need to know how to fertilize tomatoes.


Soil test before fertilization: Soil pH test kit, How To Fertilize Tomatoes

How much nutrients demand your garden soil will come out from the result of your garden soil test. Without testing your garden soil, it is difficult to apply accurate fertilization for tomatoes.

For taking the soil test, you can collect a soil test kit from the nearest home improvement or garden stores. You can also order online stores for the kit set.

Your local agricultural extension center can help you to provide the service if you found difficulties.

Which fertilizer should you use on tomato plants?

Usually, there are two types of fertilizer (natural and chemical fertilizer) which can be used for gardening and both of them perform well and also have some limitations.

Natural fertilizer:

Mainly contain organic matters like different types of manures, fish emulsion, suitable household, and kitchen garbage and other diseases free garden debris.

It is also known as organic fertilizer, homemade fertilizer or compost fertilizer which is very environment friendly.

It releases slowly in the soil and provides nutrients to tomato plants for a longer period of time. It also develops the soil quality.

You may purchase organic fertilizer from your local gardening stores or eCommerce stores like amazon.com, eBay.com, gardeners.com, organicag.com and other renowned companies.

You can also make your own fertilizer by using your household and kitchen garbage. But make sure all the nutrients represent in your homemade compost for growing healthy plants. It also times consuming and needs a place to prepare them.

You have to use an organic fertilizer at the beginning when you preparing your soil for planting tomatoes. Gradually the compost will mix with the soil and provide nutrients to the plants.

When you need to provide additional nutrients to the plants, organic fertilizer or homemade fertilizer and mulching is the best solution.

Chemical Fertilizer:

Chemical fertilizers release quickly in the soil and work faster than natural fertilizers.

If you need to provide argent nutrients to the plants, you should use chemical fertilizer.

Chemical fertilizers do not last longer and you need to maintain a schedule fertilizing depends on plants growth and demand.

Continuous and extreme uses of chemical fertilizer can infertile the soil and reduce production.

Besides, chemical fertilizer can mix with the local water sources through rain water or irrigation water. This makes water pollution and becomes a threat to the environment.

Essential nutrients for fertilizing tomato plants:

Tomato plants need nitrogen, phosphorous and potassium as primary nutrients to grow and produce fruits.

Nitrogen– helps to develop foliage.

Phosphorous– helps to grow roots, blooming flowers, and set fruits.

Potassium– fights diseases and helps to improve roots and stems.

Besides, the basic nutrients you need to provide some secondary nutrients such as calcium, magnesium,and sulfur to your tomato plants.

Calcium sulfate– also known as gypsum can prevent blossom end rot problem of tomato plants. It also develops stems health and makes the fruits more nutritious.

Magnesium –controls the process of photosynthesis, chlorophyll and maintains overall quality.

Sulfur– provides proteins and amino acids to the tomato plants. Lacking magnesium and sulfur can cause yellow leaf problem.

How to prepare the soil for tomato plants:preparing soil for tomato plants

Only providing nutrients to your tomato plants don’t bring you success.

You must also ensure the followings:

  • Proper drainage system.
  • Choose loamy and sandy soil for your tomato plants. If your soil contains a large amount of silt and clay, add a proper portion of sand, compost, sawdust, and peat moss to develop the soil texture.
  • Till the soil as much as possible.
  • Test your garden soil to provide required nutrients.
  • Keep up soil pH above 6.5 in scale.
  • At least 6 hours of direct sunlight, and avoid planting under the shade of a big tree or multi storied building.
  • Keep maintain proper spacing between two plants.
  • Mix up your garden soil with a small amount of organic matters like poultry manure or any other manure, peat moss and compost fertilizers as supplementary nutrients before planting.

How much fertilizer to use on tomato plants:

Plants need three basic nutrients from the soil to grow, develop roots, flourish, blooming, set fruit and harvest.  If you apply the basic fertilizers in the equal ratio for your tomato plants, that will be a complete fertilizer.

Most of the time tomato plants need a balanced or complete fertilizer which means a 10-10-10 ratio of NPK, which stands for nitrogen (N), phosphorous (P) and potassium (K).

How much fertilizer you need and the ratio depending on the result of your garden soil test.

If your soil contains lower in nitrogen and higher in phosphorous and potassium you should use a fertilizer like 10-5-5.

On the other hand, if your soil contains higher in nitrogen and lowers in phosphorous and potassium you can go for 5-10-10 in ratio.

If your soil slightly lacking any of the nutrients, apply a balanced fertilizer like 8-8-8 or 10-10-10

Or, if your soil naturally contains a balanced nutrient, apply compost fertilizer or slow released fertilizer depending on the soil test result.

Tomato plant fertilizer schedule: When to apply which fertilize?

You have to use tomato plant fertilizer in different stages of plant development. Apply all the fertilizer at a time is not a good idea rather it can damage your plants’ growth.

You can schedule your tomato plants fertilization process in three different stages. Such as:

1: From seedling to being mature:

Fertilize your garden soil when planting the tomato seedlings and give them a number of days to settle in the environment. At this stage,tomato plants need enough nitrogen to grow the plants and foliage.

2: Flowering time:

Once the plants become mature and start blooming flowers, reduce the nitrogen level and increase the phosphorus and potassium level of fertilizer for healthy blooming, setting fruits and developing stems.

Depending on plant growth and health condition, provide some supplementary nutrients like calcium, magnesium,and sulfur to get a better yield.

3: Setting fruits to harvest:

When the plants setting fruits, they need regular nutrients to support to produce more fruits during the season.

In that case, you need to provide schedule fertilizing of phosphorus and potassium after every 7 to 15 days’ period until the end of the season.

Provide some supplementary nutrients if needed, based on your plant’s performance.


Over fertilization of tomato plants

It is usual that plants need fertilizer and lack of fertilizer damages the plants in different ways.  But if you provide an excessive amount of fertilizer to your tomato plants, it will be also harmful. Over fertilization of your tomato plants may affect different ways:

Signs of over fertilization:

  • Using an extra amount of fertilizer in the soil produces excessive nitrogen.
  • This excessive nitrogen makes an obstacle for plant roots to absorb water from the soil and passing it to leaves. As a result, plant leaves turn yellow and become wilted. (yellowing plant leaves also may occur due to fungal and bacterial diseases)
  • Produces excessive leaves and few flowers
  • Appear brownish leaf border and tips
  • Unusual death of seedlings
  • Leaves drop off
  • Unsatisfactory plant growth
  • A crust of fertilizer on the soil surface
  • Excessive usages of fertilizer sometime attract insect pests and diseases.

How to remove over fertilization from your garden soil:

  • Remove any visible fertilizer indications appear on the topsoil like the crust of fertilizer or white salt powder.
  • Use plants like squash, cabbage, broccoli and corn which absorb the excessive level of nitrogen from the soil. In that case, do not expect a good harvest from those plants.
  • Using mulch adding scrap softwoods or sawdust to absorb excessive nitrogen from Soil.
  • Washout the excessive fertilizer by providing a strong water flow over the soil surface.
  • For your potting plants, leach the soil with water several times. This will help to come out the extra fertilizer from your plant roots.

How to control and prevent over fertilization:

  • Always apply fertilizer to plants after checking the soil nutrients.
  • Take soil tests, once planting tomatoes and twice when setting These soil tests help you to prevent excessive fertilization.
  • Get rid of the infected leaves
  • Avoid fertilizing tomato plants during heavy rain fall or windy weather condition.
  • Avoid fertilizing your tomato plants for a couple of weeks to recover the effects of over fertilization.
  • Avoid excessive using of slowly released fertilizers.
  • Develop your garden drainage system
  • Prevent adding too much soluble fertilizer in your garden soil at one time
  • Stop using soluble fertilizer several times without leaching the soil.
  • Make a proper combination of slow release fertilizer with a soluble fertilizer.
  • Steaming your potting soil following the right method to sterilize it.
  • Never transplant your tomato plants from fertile soil to a less fertile soil condition.


It is very rare to find soil that contains balance nutrients. If found, your garden plants will absorb the required nutrients and again leave the soil infertile.

So fertilize your tomato plants following the proper guidelines and enjoy the healthy fruits.

Happy tomato gardening.

Read More

Sources and Citations:

John Michael
John Michael is a self-help writer and a hobby gardener. Michael’s passion in writing is to inspire the beginner gardeners to not just “hang in there” or “make it through” but to thrive. He does this through blogging.

Leave a Reply

Your email address will not be published.