How to care for orchids: and a big watering mistake to avoid

Orchids are incredibly delicate and sought-after plants. With so many different types available, it’s no wonder that people assume they’re going to be too difficult to look after. This can put us off from buying and caring for them. 

You may be familiar with the moth orchid (also known as phalaenopsis). This the pretty variety usually on sale in supermarkets, generalist garden centres and DIY stores.  

Often, we see moth orchids bearing delicate flowers on display near the till at a supermarket or DIY store. Their petals, which can be gently speckled or blotched, are hard to resist. 

But knowing what to look for (and what to avoid) before you buy an orchid can really make a difference when it comes to keeping them alive and flowering for as long as possible at home. 

Zane Rappa, of the Orchid Society of Great Britain, explains what to look out for:

While there are some specific care tips for moth orchids, here are some general rules that will apply for most common orchid houseplants: 

• Grow in a bark/woodchip-based compost, rather than traditional compost. Westland Peat-free Orchid Compost, £3, from B&Q is perfect for the job. 
• Place in bright, but not direct, sunlight. A north- or east-facing windowsill is ideal.  
• Mist them regularly with collected rainwater. Cooled, boiled water is also useful. Avoid tap water if possible as it’s too high in salts, minerals and sometimes also chlorine.  
• Water regularly but don’t let the orchid stand in undrained water. 
• Don’t place near a cold draught. According to RHS this could cause the orchid’s flower buds to drop. 

Did you know that moth orchids differ to other orchids that grow in the ground, because they have ‘air roots’ (they’re also known as epiphyte orchids)? This means that in the wild they grow above ground, using their roots to hold onto trees – although they’re not parasitic. These air roots are coated in velamen. This is an outer layer of empty cells that help the plant absorb light and water from the atmosphere. 

This means moth orchid roots can easily rot if they’re overwatered or left to sit in water. It’s also why they’re often sold in transparent plastic pots. It might be useful to repot your moth orchid every couple of years. 

While there are some rules of thumb to follow, as with all plant care, it helps to develop your own watering routine based on your observations of your orchid’s likes and dislikes. 

The Orchid Society of Great Britain advises that you want your orchid to have a perfect balance between being wet and dry.  

“What usually works best it to wait until the [bark-based compost] becomes dry and you can clearly see roots are silvery-white in colour,” the organisation says. “You can then take your orchid to a sink to flush through with water, or if you have it in a decorative pot without holes, fill it up to the top and let it soak for a while. Drain it, shake gently, blow off any water that could have gathered on or between the leaves and put it back in its usual spot.” 

To keep your orchid as healthy as possible, wait until the plant has dried out again, then repeat this process. 

Moth orchid flowers will hopefully last a few months, provided you’ve not purchased one that’s damaged, followed the correct watering rules and placed it in a spot that suits it in your house. 

But what happens when the flowers fade? Thankfully, there’s a pruning trick from Alan Titchmarsh which might help your moth orchid bloom once again. You just need to wait until the stalks have nothing left to show. 

“The temptation is to whip the stems off now that the flowers are gone, right at the bottom,” he says in a video on Gardener’s World. “Don’t you dare! If you look down the stem, you’ll see scales [or nodules] every so often. They’re surrounding buds, and if you only cut back to where the stem has died as little, without going any further than that, then other stems can grow.” 

If a whole stem (or ‘spike’) has turned yellow, however, you won’t get flowers from this part of the plant again.  

The Orchid Society of Great Britain says you can expect your moth orchid to spike again when you notice the temperature drop. This tends to be in early autumn. The plant will then bloom in winter or spring. Blooms can potentially be induced by moving the plant to a colder place in your house regardless of season – for around two to three weeks – then pop it back in its usual, warmer spot.