Which natural fertilizers really work for orchids?

[karrolhk]

Are homemade natural fertilizers for orchids a hoax?

I am confused about whether epsom salt, rice/potato water and eggshells can really fertilize orchids. I was sceptical but I found two articles by different orchid societies in support of these natural fertilizers:

1. Article by AOS on the benefits of Epsom salts:
Epsom Salts


2. Article by Napa Valley Orchid Society on 10 natural fertilizers (including egg shells, potato water, epsom salt, etc.)
The Top 10 Natural Orchid Fertilizer Options To Grow Healthy & Optimal Orchid Plants

What do you think?

[SouthPark]

Originally Posted by karrolhk

Are homemade natural fertilizers for orchids a hoax?

Epsom salts (in suitable concentration in water) is definitely used by some very experienced orchid growers - for magnesium supply.

And crushed up egg shells is used too ----- for calcium and/or potassium supply (I think). However, I don't yet know how much time is needed to actually have the egg shell break down into a form that the orchid can use. So I've never used egg shells before.

A bottle of my liquid orchid fertiliser is lasting me years. And my bottle of mag-cal liquid supplement is also lasting me years. They're readily available, and relatively inexpensive. So I've just been using commercial products.

I haven't got a huge number of orchids ----- so the commercial product lasts me for ages.

[Roberta]

Note that epsom salts (for magnesium) and eggshells (for calcium) don't provide the nutrients that are provided by fertilizer - the major ones being nitrogen, phosphorus and potassium (NPK) Orchids don't need much in the way of phosphorus and potassium, but they do need nitrogen to grow new tissue. However, they don't need much... 1/4 to 1/2 of whatever it says on the bottle is plenty, once a week or less. If more frequent, even more dilute. Also, the calcium in eggshells is likely to not be particularly available. Whether it's needed at all depends on how much is in the water. (Where I live, there's plenty of calcium in the water... on other areas where the ground water is in contact with granite rather than limestone, perhaps not so much) Also, a commercial fertilizer also contains small amounts of trace elements that orchids benefit from. While if you ask 10 orchid growers about fertilizer you'll get 12 answers, I think few would be able to prove that the do-it-yourself approach would provide everything that the plants need. And given the tiny amount that orchids use, would be far more trouble than it's worth. Fertilizer is the least-important factor in orchid culture... get the light, temperature, watering, and air/medium/potting correct, then fertilizer may make a difference.

[Andrew-L]

Maybe Ray will chime in, he has a background in chemistry and knows alot.

On a side note, has anybody used seed sprout teas as fertilizer?

Particularly corn sprouts, mung bean sprouts, barley sprouts and alfalfa sprouts. I'd like to go organic as soon as possible and I've had success using these to fertilize cannabis.

---------- Post added at 06:13 PM ---------- Previous post was at 06:11 PM ----------

Roberta, if using RO water or distilled water with a PPM close to zero. How long do you think an orchid would last giving no extra nutrients? Would they be collecting through air roots and whatever particles are floating around?

[charlesf6]

Particularly corn sprouts, mung bean sprouts, barley sprouts and alfalfa sprouts. I'd like to go organic as soon as possible and I've had success using these to fertilize cannabis.

Pardon me?

[Roberta]

Originally Posted by Andrew-L

[/COLOR]Roberta, if using RO water or distilled water with a PPM close to zero. How long do you think an orchid would last giving no extra nutrients? Would they be collecting through air roots and whatever particles are floating around?

It will still be many months before the effects of any deficiency are noticed. Remember, the day-to-day "feeding" of plants happens by photosynthesis... they get their carbs to maintain themselves. Think of fertilizer as "vitamins", not "food". Where the lack of nutrients comes in is with growth, that's where minerals are needed to build new cells and other structures. And even there, up to a point they can "recycle" tissue that they already have, such as old pseudobulbs, spent flower spikes, etc. Orchids, particularly the epiphytic ones (most of what you're likely to grow), have evolved to be extremely efficient... in nature, they get pure water (hardly any minerals) from rain, and the only nutrients they get is what may wash down from the forest canopy... from rotting leaves, maybe the occasional bit of bird droppings. Really, really dilute. Because they grow so slowly, they don't need more. Where a cannabis plant (or a tomato for that matter) may grow a foot (1/3 m) a DAY, an orchid is likely to grow one or two pseudobulbs ( or for those types that don't have them like Phalaenopsis, leaves) a YEAR. Big difference.

[Andrew-L]

Basically, you fill a jar halfway~ with seeds, add water, cover, wait until you see tons of little baby's poking cotyledons out, then dump it into a blender. Add 1 cup of seed sprout blend to 10 gallons water. 1/2 cup for alfalfa.

Corn, alfalfa and barley during vegetative growth. Drop the corn in lieu of mung bean during flowering.

Supposedly provides growth hormones that baby seed sprouts are chock full of. Use along with compost tea and other organic foods. Used to supplement

---------- Post added at 06:38 PM ---------- Previous post was at 06:35 PM ----------

Also Roberta, Ray and I were talking via zoom the other day about how orchids feed naturally. And we both agree that there is no way the plant gets everything it needs via canopy runoff and bird droppings. There has to be a network similar to the mycohizal network terrestrial plants have under the soil, that interacts between the orchid/moss/and host tree, and not the soil.

[Roberta]

Just remember (and Ray will say the same thing), fertilizer is at the bottom of the list of cultural factors. Get temperature, light, watering frequency, medium/potting/air exchange right (90%), THEN worry about the fine points of fertilizer (10%). With everything else equal, if you over-fertilize you can kill an orchid, under-fertilize and it likely will just grow more slowly than optimal.

[Andrew-L]

How soon will an orchid tell you that it's been over fed? After it's too late? Lol

[Roberta]

Originally Posted by Andrew-L

How soon will an orchid tell you that it's been over fed? After it's too late? Lol

Yup... depending on how badly, maybe just some leaf-tip burn. Worse, root tip burn...

They really, really, really don't want much fertilizer. I get around to fertilizing my orchids maybe once every couple of weeks, a few squirts from a pump sprayer, with about 1/2 teaspoon per gallon of MSU fert. So in the grand scheme of things, a vanishingly small amount. (The more sensitive ones, like Pleurothallids, get RO water. Everybody else, rather marginal southern California city water. I water generously... sprinkler system. ) The few that really do want more fertilizer (Cymbidiums because they're big, Catasetinae because they grow fast when they're growing) will get a top-dressing of time-release fertilizer to make up for the fact that I don't give much on a regular basis. They all grow and bloom very nicely. All the photos on my website are my plants. The Species club blog (the majority of the pix are mine there too) are just examples of what's in bloom for the prior month, species only so a subset of what's blooming.