When you put salt on tomatoes for eating, it brings out the flavor and makes them taste sweeter. But if you put regular table salt on your tomato plants or soil, you will harm them badly. Don't confuse culinary salt use with gardening. Epsom salt is a different story and can help your plants in small doses.
I made the mistake of mixing these up when I first started growing tomatoes inside. Someone told me salt was good for tomatoes so I sprinkled table salt around my plants. The leaves turned brown within days and one plant died. I later learned they meant Epsom salt, which is not the same thing at all. The two types of salt do very different things to your plants.
Table salt is sodium chloride, and it's salt tomato plants harmful when you put it in soil. The sodium pulls water away from your plant roots through a process called osmosis. Your plants can't drink even if the soil is wet. The sodium also breaks down soil structure over time. This makes it harder for roots to grow and get air.
Epsom salt tomatoes treatments work well because Epsom salt is magnesium sulfate, not sodium chloride. It gives your plants magnesium and sulfur that they need for healthy growth. Magnesium helps with chlorophyll so your leaves stay green. Indoor tomatoes may show yellow leaves when they lack this mineral. Potting soil runs low on it over time.
Salt buildup causes big problems in container gardens. When you water outdoor gardens, extra salts wash down into the ground and away from roots. Container plants have nowhere for salts to go. They build up in your pot soil and can reach levels that hurt your plants even if you never add any salt on purpose.
Never put regular table salt near your tomato plants for any reason. If you want to use Epsom salt, mix 1 tablespoon into a gallon of water and use it once a month during the growing season. Watch your plants for yellow leaves between green veins which shows magnesium shortage. Only use Epsom salt if you see these signs.
Flush your container plants with plain water every few months to wash out salt buildup. Water until it runs out the bottom and keep going for a few extra minutes. This clears the salts that collect from tap water and fertilizers over time. Your indoor tomatoes will stay healthier if you make flushing part of your regular care routine.
Read the full article: Growing Tomatoes Indoors: Complete Guide
