How to fertilize tomatoes synthetically?

Plants need a variety of nutrients to thrive, and tomatoes are no exception. Fertilizers come in two basic types: natural and synthetic. Natural fertilizers are usually bulky, don’t readily dissolve in water and tend to release their nutrients slowly. Synthetic fertilizers are often made for a specific purpose or type of plant, generally dissolve readily in water and make their nutrients available to plants soon after application, though some are coated so that they release their nutrients more slowly. When fertilizing your tomatoes, synthetic fertilizers may be the perfect choice, providing nutrients just when your tomatoes need them.

1. Work a basic garden-type fertilizer into the top 6 inches of the soil before planting your tomatoes. This gets the area ready for the new crop and gives the tomatoes a boost from the beginning. Choose a fertilizer that is very low in nitrogen, N, has a high level of phosphorus, P, and is in the mid-range for potassium content, K. The three together make up the N-P-K rating that you’ll find on all synthetic fertilizers. For tomatoes, go with either 8-32-16 or 6-24-24 to get your plants off to a good start. Apply it at the rate of 1/2 to 1 pound per 50 square feet of garden area. At this point your soil is ready for your tomato plants.
2. Fertilize newly planted tomatoes with 1 cup of 10-52-17 fertilizer solution, made by mixing 2 tablespoons of dry powder per 1 gallon of water. Pour the liquid carefully around the base of each plant when you first set it out.
3. Apply more fertilizer as a side dressing when your earliest tomatoes have reached about a third of their final size. This fertilizer must contain a higher level of nitrogen to support the fruit growth, so apply 2 1/2 pounds of 10-10-10 fertilizer for each 50 feet of plant row. Place it close to but not touching the plants, and mix it well into the top inch of soil. Water your plants well to soak the fertilizer into the ground.
4. Repeat the application of a nitrogen side dressing about two weeks after you get your first harvest, and again about a month after that. Water each time, unless rain is imminent.

Because plants use nutrients in the soil, most garden soils require fertilizers to help replace those nutrients. Both organic and synthetic fertilizers do the job, but in different ways. Because they aren't water-soluble, organic fertilizers are typically slow-release, which means the nutrients are released over a period of time. The nutrients in synthetic fertilizers, on the other hand, dissolve in water, making them available for immediate uptake by the plant's roots. Ideally, your tomato fertilizer program begins with a soil nutrient test that can be performed by the local cooperative extension office. With the results in hand, you know exactly which nutrients the soil requires and the appropriate amount to use.

1. Add fertilizer to the soil when preparing to plant tomatoes. Plant scientists with the University of Missouri Extension recommend synthetic starter fertilizer analyses such as 8-32-16 or 6-24-24. Use ½-cup to 1-½ cups per 100 square feet, depending on the results of a soil fertility test. Use a hoe to mix the fertilizer into the top 6 inches of soil.
2. Wait until the tomato plant sets fruit to reapply synthetic fertilizer. Use 1 to 2 tablespoons of 10-10-10, sprinkled over the soil around each tomato plant. Water to a depth of 6 inches to soak the fertilizer to the tomato's roots.
3. Reapply the same fertilizer, at the same rate, every 10 days until harvest.