Orchids: The World’s Most Diverse Flower, in Your Greenhouse
Offering visually stunning, long lasting blooms, orchids are a wonderful addition for the beautification of your home and greenhouse. In general, orchids also have a hardy disposition, making them a good entry point for expanding into the field of flowering houseplants. There are literally thousands of species of orchids (over 100,000 if you count all the manmade hybrid varieties), so there’s a lot of options from which to choose.
This diverse collection of plants offers varying levels of difficulty for growers, from the very easy to the notoriously fussy. In this blog we’ll consider the basics of growing the majority of common orchids: ideal climate and lighting, watering and fertilizing regiments, and tips for repotting.
The first thing to note is that in their natural environment, orchids to not grow in soil. Rather, they attach themselves to the bark of other plants. Orchid potting mix is made from a blend of coarse wood chips, which allows the roots to have the proper air exposure. It’s important to note that different commercial orchid potting mixes may absorb water slightly differently, and thus may alter your watering schedule somewhat.
Orchids prefer full, but soft light, so depending on your greenhouse setup, a thin translucent curtain, or some whitewashing of the windows may be needed to avoid burning your plants. Orchids that do not get sufficient light will turn a darker shade of green and will not flower.
Nearly all orchid varieties will thrive as long as night temps do not dip below 45 degrees Fahrenheit, at which point supplemental heating will be needed. During the day, a temperature range of 60-80 degrees is ideal. Also, orchids prefer well-ventilated areas with gentle, consistent air flow and relatively high humidity: 50% – 80% is best.
Orchids do not require large quantities of water. In fact, more orchids die from overwatering than any other cause, because the roots require airflow for the plant to survive. One watering per week is often a good starting point for your plants, but there are other factors that will alter the moisture levels in your pots. The relative humidity of your setup will affect how much water is required for your orchids, and so will the type of pot and medium you’re using.
There are a few good ways to check your plant’s moisture levels if you’re unsure. One is with a finger test: if you can feel moisture in the potting mix an inch to two inches below the surface then your plant doesn’t need watering. Another way is to inspect the roots directly; there are clear plastic pots that are very convenient for orchids– if the roots are bright and green then they are well hydrated, if they turn more dull and grayish then they need watering. Clear pots are also useful for seeing when your orchids are ready for repotting, when the root structure becomes dense and crowds the space.
If your orchids are healthy, they should need to be repotted about once a year. The root medium also breaks down over this time, which is another reason to repot. If you’re not using clear plastic pots and are unsure if it’s time to repot, you can gently pull the plant out of the pot to inspect the root system.
As far as fertilization goes, a once a month regiment is all that is necessary. There are many commercially available fertilizers made specifically for orchids, but any all-purpose fertilizer that contains equal or near equal amounts of N, P, and K is perfectly sufficient.
Once you have the basics down, you may want to try your hand at harvesting orchid seeds and producing them yourself. This requires some very involved techniques but can be rewarding to the ambitious gardener.
Fun fact: you have the vanilla orchid to thank for your flavored latte!