If you buy a commercial product, be sure to carefully follow the application instructions on the label. If you’re making your own spray, choose ferrous sulfate that is 20-22% iron. Try adding 2-3 drops of dishwashing soap for every 1 US gal (3. 8 L) of either commercial or homemade spray. This will help the spray adhere to the plant’s leaves.
Once the fall hits, the plant will start to become dormant, and it will remain dormant through the winter. During this time, the iron won’t have much effect, even if the plant retains its leaves through the winter. [2] X Research source
If the iron burns the leaves, the edges will start to curl and turn brown.
It’s fine if some of the spray gets onto the ground around the plants. However, since the solution isn’t strong, it’s not likely to have much of an effect on the iron content of the soil. You’ll likely notice results in just a few days.
Even though this isn’t a long-lasting fix, it can help keep your plant healthy while you work to improve the soil.
Both powdered and granulated iron will be easy to mix into the soil, and they’ll be readily absorbed by the plants. You can find chelated iron at many big box stores, lawn and garden stores, or online. Make sure the label indicates that all of the iron in the supplement is chelated. Some iron supplements will say “chelated” on the label even some of the iron is in a different form. [6] X Research source Also, if the supplement you’re using contains a fertilizer, be sure it doesn’t have phosphorus in it. Too much phosphorus in the soil can contribute to iron deficiency. [7] X Research source
Either way, you’ll probably have to reapply the treatment once a year, so just pick the time of year that will be most convenient for you every year.
If you’d prefer, you can also dissolve the iron in water, then spray that around the base of the plant. This is a good option for treating shrubs, smaller gardens, or individual trees, but since chelated iron can be expensive, it’s not ideal for treating larger areas.
Don’t mix these ingredients in any pots or bowls that you plan to prepare food in later on. Read the label to make sure you’re choosing a ferrous sulfate product that contains a high concentration of iron. Wear gloves and eye protection when you’re working with iron sulfate. Also, work in a ventilated area, and consider wearing a respirator if you’ll be working with large amounts.
Be sure not to dig so deep that you damage the plant’s roots. [12] X Research source Check with your local utility companies before you dig in an area that might have utility lines.
4 holes for a 1 in (2. 5 cm) diameter 6 holes for a 2 in (5. 1 cm) diameter 8 holes for a 4 in (10 cm) diameter 12 holes for a 6 in (15 cm) diameter 16-24 holes for an 8 in (20 cm) diameter 25-30 holes for a 10 in (25 cm) diameter 30-40 holes for a 15 in (38 cm) diameter 40-50 holes for a 20 in (51 cm) diameter
Be careful not to get the iron on your skin or in your eyes, and avoid breathing it in.
If you used an augur to make your holes, it should have removed the dirt, rather than just compacting it. That will ensure you have the excess soil you need to fill the holes back in. This treatment will typically last up to 2-4 years, so you shouldn’t have to repeat the treatment until the next time the plant shows symptoms.
