Epsom Salts is magnesium sulfate and and will fix magnesium deficiencies. You can buy a 1kg box from any supermarket, most hardware stores, or even health food shops for a couple of dollars. Supermarkets are generally the cheapest and work fine. Just make sure it doesn’t have perfumes added to it.
You need to add Epsom Salts to hot tap water and stir it up to get it to dissolve, then add that to a watering can with cold tap water and water it on the plants once or twice a week until the problem is fixed.
I use about 1/3 of a level teaspoon of Epsom Salts in a 9 liter (bit over 2 gallon) watering can each time I fertilize the plants. I use the same dose for calcium chloride and add them together. You can use a higher dose rate (1 level teaspoon per 9 liters of water) but the more you use the more it raises the pH of the water. If the pH goes too high the plants won’t be able to use the magnesium or calcium so just add a little bit regularly rather than a lot occasionally. I can water 2 x 30cm pots with the 9 liters of water.
If the plant has a calcium deficiency you can add lime (calcium carbonate) and sprinkle it over the surface of the soil and then water it in. You can also use calcium chloride (available from hardware stores or places that sell swimming pool salt to some water and water it on the soil.
Calcium chloride dissolves easily in cold or warm tap water. Lime doesn’t dissolve easily in water and is more of a slow release calcium additive. I prefer calcium chloride mixed with water because you see quicker results.
Nitrogen comes from poop and pee. You can pee on the soil under the plant a couple of times a week or dilute your urine (water it down) and use it more regularly. If you get a pelletized chicken manure, sheep poop or cow poop you can put that on the soil for nitrogen.
Don’t use raw/ fresh manure, especially not fresh chicken poop because it burns the roots. Any manure should be composted for at least 3 months before use and 6 months is better and safer.
Horse poop is usually full of undigested weed seeds and has to be composted for months before using it to stop the seeds popping up in the soil under your plants. You can just pull the weeds out or use vinegar to kill them.
If you need a safe herbicide to kill weeks, use 2 liters (1/2 gallon) of white vinegar and 2 tablespoons of liquid soap. Mix them up and spray on the weeds. The vinegar is acidic and burns the plants. The soap helps the vinegar stick the plant leaves. You can also spray straight vinegar on the weeds without using soap.
Use vinegar on dry days so it doesn’t get washed off. It works well in hot dry conditions when the weeds are already stressed from heat and dry conditions.
