Epsom salt is made of magnesium and sulfur. Magnesium promotes seed germination and chlorophyll production, and it also facilitates the plants' absorption of phosphorous and nitrogen. Besides, Epsom salt offers an advantage over synthetic fertilizers: Despite its name, it's not a salt, and it doesn't leave residue behind in the soil that creates a salt buildup or harm plants. Feed your tomatoes Epsom salt once every two weeks for a plant larger and more fruitful than last season.
Measure your tomato plant to calculate how many tablespoons of Epsom salt you'll need. Use 1 tbsp. for every foot of plant. A 6-inch-tall tomato plant, for example, takes ½ tbsp. of Epsom salt.
Sprinkle the correct amount of Epsom salt around the base of your tomato plant.
Mix the Epsom salt crystals with the soil, working them into the ground carefully to avoid damaging the roots. Use your fingers or a trowel.
Irrigate your tomato plant to dissolve the crystals, releasing the nutrients into the soil.