DIY cal mag recipes

[Peat Phreak]

DIY cal mag without nitrogen:

1.5g / gal - Gypsum powder
1g / gal - Epsom salt


DIY cal mag with nitrogen:

1.5g / gal - Calcium Nitrate
1g / gal - Epsom salt


Both formulas have an approximate cal mag ratio of 3 to 1 when mixed with average tap water. Both formulas contain 50% of the total cal mag requirement per feeding. Both are considerably less expensive than buying bottled cal mag.

Most bottled cal mag contains nitrogen. A typical grow that needs a cal mag boost often does NOT need a nitrogen boost. The extra nitrogen can cause problems. That is why I prefer the formula without nitrogen most of the time.

Bottled cal mag usually contains some iron EDTA. I skip that because my other nutes have plenty.

 

[Peat Phreak]

The fastest and most reliable way to fix a cal mag issue is to spray it on the leaves. It can fix it in one or two treatments. Foliar cal mag can also be used to prevent issues from occurring in the first place.

If I spray some cal mag twice a week from seedling to veg, leaf issues don't occur. If I skip the foliar, minor leaf issues are more likely to occur in the early stages of growth.

 

[Peat Phreak]

Handy info for foliar feeding absorption rates of various nutes

Magnesium has the fastest absorption rate and it's one of the most common deficiencies we see.