Starting with your first watering you are going to want to switch to a more general fertilizer than 10-52-10, as we used this to promote root growth and your tomato plants should now be starting to take hold in the garden. Lets go with 15-30-15 or something to the equivalent, 20-20-20 also works good and apply it weekly until fruit set.
One of the best and recommended ways to properly fertilize is by watering can and with a moist soil. So once per week while watering and after letting the drip/soaker hose run for about ten minutes, mix your fertilizer as per label directions (I usually ad 1litre of water just to mix the fertilizer up as you will have more than enough with watering your beds) and apply it per plant.
Some people use other methods, but with this you will know exactly how much each plant is getting. When fertilizing your plants keep in mind to apply it near the base of the plant in a radius of no more than 1 sq. ft. in all directions and then apply to a radius of 2 sq. ft. after fruit set and never apply fertilizer from above the plant except when applying a foliage spray as we don’t want to possibly burn the plant.
Once fruit has set you now want to switch to a fertilizer to promote fruit growth miracle grow makes 18-18-21 for tomatoes, but for growing giants go even higher than this. Schultz has as well a tomato fertilizer which is a little more useful, 18-19-30. Some people prefer to use a general 15-15-30 which is fine to. Keep applying fertilizer weekly regardless of the type till harvest.
Another thing I will touch on is a foliage spray, while some apply every type of concoction known to man. I recommend using compost tea and I'll discuss this below. Apply it once per week using a mister (spray bottle set to mist) and mornings are best as you don’t want to leave moisture on your plants overnight (leaves, fruit etc.) as this is just asking for trouble.
