HOUSEPLANTS > ORCHIDS > FEEDING
By KERSASP SHEKHDAR Kersasp Shekhdar, Gardener Kersie is a professional and vocational writer who learnt the basics of gardening as a toddler, courtesy of his grandfather. He is an active gardener with a preference for flowering plants. Peter Lickorish, MHort (RHS) - Horticulturist Peter is a Horticulture Lecturer and self-employed Horticulturist, with a passion for diverse areas of the industry - from garden design to the science behind plant growth and propagation. He has completed the Royal Horticultural Society’s Master of Horticulture (MHort) Award and lectures on RHS courses at Bedford College. Malcolm Moodie, Chairman of the Solihull & District Orchid Society Malcolm has been growing orchids for 30 years and had lots of experience searching for, growing and caring for orchids. He previously ran his own business providing orchid sundries to hobbyist growers and he also delivers lectures to various orchid and gardening clubs across the UK. Malcolm is currently the Chairman, Vice President and Show Secretary of the Solihull & District Orchid Society.
Reviewed By PETER LICKORISH 
Contributions From MALCOLM MOODIE 
IN THIS GUIDE
- The Wrong Growing Medium
- Repotting Considerations
- Feeding Your Orchid
- Periodic Flushing
- References
ORCHID GUIDES
Dendrobium
Feeding
Phalaenopsis
Reblooming
VarietiesWatering
Orchids, so often mistakenly considered native to a particular type of tropical ecology, grow in an incredibly diverse array of ecologies and regions.
Though a very large number of species are found in cloud forests, such as those of Costa Rica (whose national flower happens to be an orchid), these plants grow in the sparse ground at sea level, on treetops in rainforests and everything in between.1Orchids of the Cloud Forest. (n.d.). Cloudbridge Nature Reserve. Retrieved April 20, 2023, from https://www.cloudbridge.org/wp-content/uploads/2011/11/NatureNotesNo15.pdf
Perhaps this is not too surprising because the Orchid Family includes 850 genera and nearly 30,000 species.2Johnston, E. (2022, February 28). Exploring the orchid family tree. Kew Royal Botanic Gardens. Retrieved April 20, 2023, from https://www.kew.org/read-and-watch/orchid-family-tree
So how do you set down fertilising and feeding guidelines for such a diverse plant family?
Ifs and buts out of the way, please bear in mind that what follows are general guidelines that are suitable for most orchid varieties grown by hobbyist gardeners.
However, other factors will certainly influence how well or how poorly your orchid plants respond to fertilising, as laid out below.
| Difficulty | Easy |
| Equipment Required | Low-nitrogen, high-potash formula or a balanced formula |
| When To Feed | Once a week in the flowering season, every 20 days in the off-season |
The Wrong Growing Medium
Before going into the particulars of feeding orchids, I need to cover a necessary preliminary: the growing medium.
If you have obtained your orchid plant from a professional grower or an established nursery, you can skip this section, but if your orchid was purchased from a supermarket’s plant department or from your corner garden centre, read on.
Purely commercial operations may or may not root a plant in the most suitable type of medium.
For the large majority of plants, this horticultural inexactitude does not matter much and a multi-purpose compost usually works out fine.
This is not the case for orchids.
First off, free-draining medium is a non-negotiable for these plants.
Any waterlogging or constant damp can bring about root rot.
Next, these unusual plants by far prefer to be rooted in poor, low-nutrient media, though at the same time, they respond wonderfully well to regular feeding!
So, if your orchid plant came from a garden centre or a supermarket, I’d suggest you play it safe and re-pot it in a suitable medium.
Repotting Considerations
Do not repot an orchid plant when it is in bloom, which will almost surely be the case when you buy it.
Wait until it has finished flowering or until spring when fresh growth is emerging.
In other words, repot your orchid when it is in active growth but not during its flowering season or during winter dormancy.
You can purchase a specialised medium such as Westland Orchid Potting Mix or Miracle-Gro Orchid Potting Mix or you can make your own.
A good medium for a potted orchid would be composed of fir bark, perlite and sphagnum moss.
Other components that could be added or used as substitutes include grit, pine bark and peat moss.
Grit may be needed to give stability to stop top-heavy pots from falling over.
In what proportions, though?
Actually, the ideal composition varies from genus to genus but you can’t go wrong with a basic mix of 3 parts fir bark, 2 parts perlite and 1 part sphagnum moss.
Feeding Your Orchid
Perhaps it is somewhat counter-intuitive that a plant that prefers poorish soil benefits greatly from some serious feeding.
However, the style of feeding plays a key part.
What these plants respond very well to is frequent feeding but in small doses.
“Use a good fertiliser that does not contain urea and has many macro and micronutrients needed for orchids,” Malcolm Moodie from the Solihull & District Orchid Society shares.
Also, feeding should be done for all twelve months of the year.
However, the formula and frequency of the fertiliser that is used differs depending on the season, as Malcolm explains:
“Regular feeding using a balanced feed or slightly higher nitrogen feed (Grow Formula) in the summer with a low Nitrogen feed (Bloom Formula) in winter will help.”
So in the off-season, use a balanced formula, such as a 20-20-20 once every 20 days.
During the blooming season, opt for a low-nitrogen, high-potash formula, such as a 10-20-30, and apply it once every 20 days from winter, increasing to once a week during peak flowering.
Use the first type from the time the blooming season winds up until you see the first flowering stalk or the first bud.
Then, switch to the second type and use it through the blooming season.
Typically, these timeframes will run from sometime in October to sometime in March and vice versa.
Feed when you water by adding in the fertiliser and applying in the same way you would water.
“Misting water, mixed with fertiliser, to the underside of orchid leaves enables it to be taken in through stomata pores,” shares Peter Lickorish, a Master Horticulturist.
“I find a mixture of foliar feeding in this way, and applying fertiliser to the medium and the roots through a watering can with a narrow spout, not a rose, is ideal.”
How much fertiliser you use depends on various factors, including the age and size of the orchid plant and the size of the pot.
Do not feed an orchid plant at all in its first year.
We recommend that you use about 75% of the concentration or volume recommended by the manufacturer. Apply at a lower concentration during winter.
Use a liquid formula or make your own liquid using powdered fertiliser, but remember to use rainwater or distilled water.
Periodic Flushing
It is possible for salts to build up in the growing medium.
Therefore, twice in the off-season and twice during the blooming season, skip a scheduled feeding and, instead, drench the medium, allowing the water to flow out from the drainage holes, so as to flush out any built-up salts.
Such flushing is critical for some genera that are intolerant of salts build-up, such as pansy orchids.
Resume watering and feeding as usual promptly after (but only after) the medium has dried out.
- 1
Orchids of the Cloud Forest. (n.d.). Cloudbridge Nature Reserve. Retrieved April 20, 2023, from https://www.cloudbridge.org/wp-content/uploads/2011/11/NatureNotesNo15.pdf
- 2
Johnston, E. (2022, February 28). Exploring the orchid family tree. Kew Royal Botanic Gardens. Retrieved April 20, 2023, from https://www.kew.org/read-and-watch/orchid-family-tree
