We have already broken the myth that you should fertilize orchids with coffee grounds. But what about eggshells? Is it okay to use them in the care of the popular houseplants and what to look out for? In this article, we explain the benefits of eggshells for orchids and how to use them properly.
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What are the advantages of eggshells for orchids?
Eggshells are rich in calcium, which to some extent can prevent root rot in orchids. An orchid that has a higher calcium content will be less susceptible to the negative effects of root rot. But beware: no amount of calcium can reverse the effects of overwatering the plant, and calcium itself is not a preventative against rot.
If it is in fine powder form, the water will pick up the calcium from the top of the pot and bring it into the substrate. In the orchid substrate, the calcium reacts with the excess salt and reduces the amount of sodium. This is especially beneficial when overfertilizing.
Eggshells can provide these nutrients to your orchid
Eggshells are nearly 94% calcium carbonate, which is mostly pure calcium. When ground into a fine powder and sprinkled over the substrate, eggshells also provide numerous trace elements in smaller amounts: Copper, iron, magnesium, phosphorus, potassium and zinc. All of these elements can enhance the growth of your orchid and are not usually found in commercial fertilizer. (Most store-bought orchid fertilizers usually have three ingredients in varying proportions – nitrogen, phosphorus and potassium, but no calcium).
But: eggshells cannot replace commercial orchid fertilizer. However, they are good for supplementing the elements that are not in the NPK fertilizer.
What are the signs of calcium deficiency in orchids?
Because of the way calcium is absorbed in the plant, calcium deficiency first shows up in the youngest leaves. You can tell that your orchid needs more calcium when the leaf tips become deformed.
Also, pseudobulbs, leaves and stems are no longer as plump and lush as growth is inhibited by the calcium deficiency. Calcium deficiency in orchids results in smaller plants and inhibits their full growth. If you take a look at the roots, you will still see brown and black roots, a clear sign of future (if not already present) root rot.
Once the calcium has settled into the cell wall, it strengthens it, making it more resilient and stronger. This leads to stronger leaves and, in the long run, a larger, fuller, more vibrant orchid.
Fertilize orchids with eggshells: Here’s how
Now, if you already know that orchids will benefit from the nutrients contained in eggshells, we need to explain in more detail how to make this natural fertilizer yourself. The options are two:
- Grind eggshells into powder (use 1-2 times per year): Gather your eggshells (at least from 10 eggs) and clean them inside and out with warm water to make sure no egg white or-yellow remains. Then lay them out on a kitchen towel overnight or until completely dry. Once the eggshells are dry, place them in a food processor, blender or coffee grinder and grind until they are the consistency of a grainy, somewhat coarse powder. To fertilize your orchid, mix a few tablespoons of eggshell powder into the substrate at the top of the pot. Do this just before watering, as this will help the fertilizer to be absorbed.
- Make liquid eggshell fertilizer (use 1 time per month or every other month): Boil 12 to 24 eggshells in water for one hour. Let the shells sit in this water overnight. Remove the eggshells the next morning and use the water to water or spray your orchids. This is also an excellent way to remove chlorine from the water as it evaporates when boiled.
Avoid overdose at all costs
Eggshells have been shown to be beneficial to your orchid when used in sparing amounts. Do not use too much or the calcium will become harmful and even toxic.
In larger amounts, calcium will interfere with the plant’s absorption of other nutrients. The excess calcium will compete with the other nutrients and win every time. The orchid will not absorb less phosphorus, potassium, magnesium, boron, copper, iron or zinc, but none at all.
If there is an excess, calcium will gain the upper hand, even if these substances are present in the orchid soil. In other words, do not use the crushed eggshells every other month, but only once or twice a year.
If you choose to use the water boiled with eggshells, you can do it once a month or every other month.
Summing up eggshells and orchids.
A homemade fertilizer made from eggshells will benefit your orchid by strengthening the orchid’s cell walls, making it more resilient and less susceptible to external factors such as root rot. The calcium from eggshells also reduces salt formation and prevents chlorosis. The cells become more stable and solid, and in the long run the orchid will grow bigger and healthier.
Also interesting: Why coffee grounds are not good orchid fertilizer ?