Adding calcium to orchids

[ALToronto]

Epsom salts is magnesium sulfate. You need both calcium and magnesium, together, at the same time. They work for plants just like they work for people and animals. Ca:Mg should be anywhere from 2:1 to 4:1. So whatever you add in MagiCal, you should add about 1/3 in Epsom Salts.

[tucker85]

Magical is a good product, Kailyn. I've been using Magical for several years now. During the spring and summer growing season I use it at 1 teaspoon per gallon, twice a month. I generally apply it by itself but I know growers who just add it to their regular fertilizer twice a month or at a 1/2 teaspoon once a week. You don't need to use epson salts if you use Magical.

---------- Post added at 08:12 AM ---------- Previous post was at 08:02 AM ----------

Originally Posted by LadySoren

What exactly does calcium do for plants again...?

LadySoren, calcium is used by the plant to build strong cell walls. If there isn't enough calcium available, the new growth will have thin cell walls and that will leave it susceptible to fungus and insects. If you see some of the new growth turn black and rot, it's a sign of calcium deficiency. If you don't have fungus problems then your orchids are probably getting enough calcium from your tapwater or your fertilizer. Growers who use rainwater of RO water should use a calcium/magnesium supplement. Also some orchids, like paphs and hybrids of C. walkeriana, need higher concentrations of calcium than other orchids do. According to owner of Gold Country Orchids, too much calcium doesn't hurt orchids so that isn't an issue.

[naoki]

Interesting info, Tucker. If you look at plant mineral nutrient textbook, Ca is well-known to interfere with uptakes of other cations. So if you give too much calcium, I would expect that plants may suffer from other deficiency (I don't know much about plant nutrients, so this is just my guess). But you probably have to do something extreme to cause the problem. Also, we don't know much about nutrients of epiphytes who are accustomed to really low concentration of mineral nutrients, so the textbook may not apply to orchids.

Good info about Ca vs Pathogen! A small trivial point is that Ca deficiency can influence the adhesion between cell walls (not the thickness of cell walls). Between cell walls, there is a glue like material called middle lamella, which is rich in Ca. Some (not all) pathogens secret enzymes to break the middle lamella, to get into plants. Ca is also involved in osmo-regulation (cells with strong internal pressure vs limp cells), which is the mechanism by which plants open/close stomata. That's my understanding, but please correct me if I'm wrong.