I like to get water and nutrients deep into the soil beneath my tomato plants. This encourages a strong root system and a more sturdy plant overall. Plus, a deep watering means I don’t have to worry as much about the plant drying out on those hottest of summer days.
I use a juice bottle with the end cut off and the top removed.
I like to add some compost to the feeding bottle. Occasionally I add Epsom salts this way as well, providing the plants with much needed magnesium.
Just add water and let that absorb over the next several hours.