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

If you’ve ever tried to research how to care for orchids, you’ve probably been met with a lot of contradictory information.

That’s not surprising. According to Kew, there are nearly three times as many orchid species as there are species of bird alive on Earth today (around 28,000). Considering you can find them on every continent, in all types of growing habitat, there will be many different ways to help any species that can survive indoors thrive.

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 pretty variety is usually on sale in supermarkets, generalist garden centres and DIY stores.

How to care for moth orchids – before you buy

Avoid these tell-tale signs of neglect

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:

• Don’t buy orchids that have been cold: These tropical orchids need temperatures between 15-35°C (59-95°F). If it’s a chilly autumn day, and the orchids are placed outside or near the door, it’s likely they are already going to be quite damaged.
• Check the leaves: Don’t choose a plant that has yellow leaves. It doesn’t matter how beautiful the blooms are – it means the plant has started to rot. 
• Choose the right balance of blooms: The perfect time to buy an orchid is when half of the spike (stem) is still in bud and half of the flowers are open. Plants like this can continue to bloom for up to three months.
• Check the root system: You want to see robust, sturdy roots – take one between your finger and gently squeeze it. If it feels mushy and is brownish in colour, cut it off with sterilised scissors when you’re home. Tidy the whole root ball, rinse it off in the sink or hose it down in the garden.You might need to repot it, if necessary, as soon as the blooms fade.

How to care for orchids: the essentials

Create the right conditions for growth

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, 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.

How to care for orchids when watering

Why it’s crucial to avoid overwatering

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.

How to water an orchid the right way 

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.

How to care for orchids after flowering

Top tips to encourage future blooms

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.