Fertilizing Tomatoes

Once your tomatoes are growing well, you may wonder what else you can do to keep them healthy. Many gardeners focus on fertilizers as a growth enhancer for their tomatoes. This usually works, but there is a better focus for what your tomato plants really need if they are to thrive and give maximum yields.

When to Fertilize Tomatoes

The absolute best time to fertilize is before the tomatoes are even planted. Fortifying the soil beneath the plants before the plants are added to it means that the nutrients are already there, ready to be unlocked, and you run no risk of “burning” or other adverse effects from fertilization while the plant is growing.

If your plants are already growing, then use small amounts of fertilizers or use organics that do not burn (such as compost and light manures). A good rule of thumb is to sidedress every month with a low nitrogen fertilizer. Too much nitrogen will cause the tomato plant to focus on the plant itself and not setting fruit.

The best time of day to use most fertilizers is in the evening, when the sun is waning, and after watering or a rain. Chemical fertilizers can wash through without leaving much benefit in the soil if they are watered after application and they can “bake” in the sun and either lose potency or burn the plants as well.

Compost and light manure (such as chicken leavings or vermicompost) can be used at any time. It should be spread lightly over the ground around the plants. Do not dig it in or otherwise disturb the soil as this can harm the tomato’s roots.

How To Fertilize Tomatoes

The best fertilizer for tomatoes, whether while they are growing or before planting, is extremely fertile soil. Compost is your best source for creating this. Manure (composted bovine, chicken, worm, etc.) is also excellent, especially as a pre-treatment for soil before planting.

If the plants are not in the soil, then mix the compost in well with the upper layer (first two or three inches) if you can. If not, spreading it over the top of the soil and allowing the rain and maybe your own watering to push it into the soil. If you compost/manure your soil in the week or two before planting and again after harvest before winter, within a couple of years you’ll have some of the best garden soil on the planet. Keeping up this regiment twice yearly means no need for artificial spraying or fertilizing without sacrificing awesome yields.

Good Tomato Fertilizers

Commercial Tomato Fertilizers

Commercial fertilizers meant specifically for tomatoes are available. Most are potassium-rich because once flowering begins, tomatoes will need to focus on fruit production rather than the growth of the plant.

Chicken Poop Fertilizer for Tomatoes

For the organic grower, though, things are a little simpler. If at all available, use chicken scratch and leavings. This can be spread around the plants at any time, but if you have only one shot at it, do it when the first buds just begin appearing on the stems. The leavings of chickens are usually very rich in both potassium and nitrogen, especially if the chickens are ranged (not cooped up).

Cow Manure for Tomatoes

Cow manure is another great one, though it is really best used before planting and after harvest. Avoid manure from dairy farms as they are often given a lot of salt, which leaves sodium in the soil – not good for plants in large quantities.

Compost for Tomatoes

Compost is good for tomatoes at any time you want to add it. Quality compost, either made yourself or purchased (beware of some problems this could have, such as diseases in the compost), can be spread on the ground around the plants to add nutrition to the soil.

Compost Tea for Tomatoes

Compost tea is probably the best way to inject nutrients directly to the plants without cutting into the soil. It can be poured directly onto the base of the plant to soak into the roots. Most compost tea is nitrogen and potassium rich as a function of how it’s made. Manure tea is also a good substitute if compost is not available for brewing.

Although the plants are usually the focus, remember the true secret to a lush, healthy, productive garden: Plants are only as good as the soil. Focus on soil health!

Want to learn more about fertilizing tomatoes?

Check out these helpful websites:
Best Time to Fertilize Tomatoes from NC Cooperative Extension
Growing Home Garden Tomatoes from University of Missouri Extension