Tomatoes are arguably the most popular plant grown in the home vegetable garden, and tomato fertilizers are a hot topic. Tomatoes are very hardy plants and can be grown in almost every hardiness zone.

One of the most frequent questions many tomato gardeners ask is, "What is the best fertilizer for tomatoes?". Tomatoes may need fertilization at certain times of their growth depending on what available nutrients are in the soil. You can find more on when to fertilize tomatoes here - when to fertilize tomato plants.

Here are the best fertilizers for tomatoes.

Find Out What's In Your Soil First

Heirloom Tomatoes
Before fertilizing your tomatoes, you need to find out what nutrients are already available in your soil.

If your soil has high levels of nitrogen, there may be no need to add more nitrogen.

It's unlikely your soil has high levels of nitrogen, because the nutrient easily leaches from soil, but it's just an example.

The best way to determine your nutrients levels in the garden soil is by performing a soil test. Home soil test kits can tell you some primary information, such as macro-nutrient levels and pH.

For a complete soil analysis it is best to have the test completed by your local cooperative extension. They will be able to analysis your soil for all macro and micro nutrients in your soil, plus lead and mercury levels. A soil analysis is generally inexpensive, ranging from $7 to $15 depending upon location.

Different Nutrients for Different Stages of Growth

Tomatoes need different nutrients at different stages of their growth cycle. Generally, when planting it is a good idea to add more phosphorus, because phosphorus helps to develop strong roots. Developing the root system is very important during the early growth of the tomato plant.

Once the tomato plant is established the levels of potassium can be slightly raised for vigorous plant growth and to help establish fruits. A good source of potassium is wood ashes from a fireplace that is worked into the soil.

High levels of nitrogen should be avoided. Although tomatoes do need some nitrogen for foliage growth, too much nitrogen can create big, bushy tomato plants but less fruit. Here are the best fertilizers for tomatoes and when to use them.


High quality compost is created from decomposed organic matter and can be added around tomato plants throughout the year.

As a matter of fact, it is recommended that compost be used as a fertilizer for tomatoes during the entire growing season. Before planting tomatoes, mix compost in the soil at a depth of about three to six inches. Work the compost in the soil well using a garden fork or hoe.

Once the tomato plants have become established, fertilize them with compost as a side-dressing around plants about once a month.

Enriching your garden soil well with compost will give your tomatoes all the nutrients they need throughout the season. Compost will also improve soil structure, which in turn will improve soil drainage and provide beneficial microbes.

Tomato-Tone Organic Fertilizer

Tomato_tone Tomato FertilizerTomato-Tone Organic Fertilizer is a natural, granule fertilizer for tomato plants derived from plant materials and other organic matter.

It features a N-P-K rating of 3-4-6, that's 3% nitrogen, 4% phosphorus, and 6% potassium. Tomato-Tone also contains beneficial microbes which encourage root development and strength.

Tomato-Tone can be used when transplanting tomatoes in the garden and once the tomato plant has become established. Just use a handful of Tomato-tone per plant.

For more information on how I use Tomato-Tone fertilizer on my tomato plants, see Fertilizing Tomatoes.

Tomatoes Alive!

Tomatoes Alive! is another granule fertilizer for tomato plants that aids photosynthesis, encourages root development and provides beneficial soil microorganisms. It is a slow release fertilizer that gives tomato plants the nutrients it needs as it develops, eliminating the chances of stress and burning.

Tomatoes Alive! only needs to be used on tomatoes twice a year for fantastic tomatoes.

GSC Organic Tomato Fertilizer

GSC Organic Tomato Fertilizer

Gardener's Supply Company's Organic Tomato Fertilizer is a slow-release granular fertilizer for tomatoes that boasts a 5-6-5 guaranteed analysis and gives tomatoes all the essential minerals they need. It also includes plenty of phosphorus for big, abundant fruit.

Mix GSC Organic Tomato Fertilizer in the soil when transplanting and use as a side-dressing several times throughout the season. It's all natural formula will not burn plants, and it conditions the soil for great root growth.

Compost Tea

Although compost tea is not actually a fertilizer, but it is an important part of growing amazing tomatoes. Compost tea acts as a soil conditioner, softening the soil making it easier for tomato plants to absorb nutrients.

Compost tea has been known to help prevent disease and some pests in plants. It can be applied directly to the plant and to the soil around the plant once a week for optimum results.

Grow Fantastic Tomatoes