As your tomato plants begin to bloom side dressing your plant with a fertilizer may increase your plants health and fruiting ability. Drizzle about an ounce of 5-10-10 fertilizer in a ring around the plant. Just be sure not to get any on the leaves, rinse off if you do. You can also try manure tea by mixing 1 part manure to 2 parts water and water the plant every few weeks.
That being said, be careful. Over fertilizing, as much as under fertilizing, can cause damage to your plants. Too much of one fertilizer will make your plant produce great leaves but no fruit, too much of another can cause fruiting but a weak plant that is susceptible to disease. General rule of thumb when fertilizing, do it with a weak concentration of fertilizer. This leaves you with the option of being able to fertilize again at another time...it’s hard to take away an overdose of fertilizer.
Looking forward to a great tomato crop this year!