How to take care of orchids in water

I first came across water culture for orchids about 5 years ago. My immediate reaction was horror. I’ve been growing orchids for over 30 years and the thing that kills more orchids than anything else is overwatering. Now people suggest submersing the roots in water full time – that’s crazy – or is it?

Some people seem to be able to grow them well in water. The picture below is a large glass vessel containing several phalaenopsis orchids in water culture and they seem to be doing well. I am also part of a Facebook group dedicated to orchid water culture and I have personally tried both full and semi-water culture. In this post I will review the pros and cons of the technique and give you my impressions. I will answer the question, is this a good technique for growing orchids?

Growing Orchids in Water Culture – Is it A Good Idea?

What is Orchid Water Culture?

In simple terms it is growing orchids in more water and there are three main techniques: full water culture, semi-water culture and semi-hydroponics.

Based on how people use these terms you would think they are well defined, but they are not. Everyone has their own definition, but these are the more popular ones and the ones I use.

Full Water Culture for Orchids

The word full is a bit misleading because in most cases the roots are not fully submersed in water. Some people do fully submerse them, but most will submerse only 2/3 of the roots, or even 1/3 of them. The key to this method is that some part of the root is always in water. It is common, when starting a new orchid with this technique to have the roots sit above the water line and let them grow into the water.

Semi-water Culture for Orchids

This technique has the roots sitting in water for a few days, and then the water is removed so the roots can dry out. This wet-dry cycle can be 2 days wet and 5 days dry (a common cycle), or 5 days wet and 2 days dry or any other variation that suits you.

Semi-hydroponic Culture for Orchids

This technique is even more variable. There is some inert material in the jar (leca clay pebbles, pumice, stones) and some water. The water level can be at any height and it can even be drained periodically to give the plant a dry period. From an orchids perspective this method is really the same as the above two techniques, so I will ignore it in this post.

What Orchids Can Be Grown in Water Culture?

Most epiphytic orchids can be grown this way but the focus has been mostly on the moth orchid, the phalaenopsis, which is by far the most popular home grown orchid.

Does Water Culture Work?

There is no doubt it works. Plants are very adaptable and you can grow them a lot of different ways. Based on the pictures that I have seen, flowering is better in pot culture than water culture. The above picture is a rare exception.

Rather than ask does it works, we should ask the following.

• Is water culture better than traditional pot culture?
• Is it an easy method to use?

Claimed Benefits of Orchid Water Culture

There seems to be a lot of interest in this technique so I figured there must be some good reasons why people are trying it. I asked for reasons in a Facebook Group that is mostly dedicated to water culture and only got three answers. I then went looking at blog posts that promote the method and found almost no claimed benefits. Here is the total list of what I found.

• Fewer fungus gnats
• Fewer pests
• Less work
• Easier to monitor root problems

I also found this statement, “water culture mimics the natural way orchids grow”. That is nonsense. In nature orchids get rained on and then dry quickly. Some do grow in tropical areas but even in rainy seasons when it rains all day the roots do not sit in water because they are mostly running vertically along tree trunks. They are wet but not submersed in water.

To understand these claimed benefits we have to compare them to the traditional way of growing orchids which is in bark or more commonly coconut husk. Sphagnum is also used but it is a more difficult media for beginners and I don’t recommend it, because it kills too many plants.

Culture in coconut husk is simple; you repot every two years which takes 10 minutes, and you water and fertilize once a week which takes less than 5 minutes. You can see full details for this method in this playlist of YouTube videos.

Fewer Fungus Gnats

Not sure why this claim is made. Properly water orchids don’t have fungus gnats. This video will show you how to get rid of fungus gnats in potting soil: Getting Rid of Fungus Gnats.

Fewer Pests

The common pests on orchids are mealybugs and scale. Both of these live on the foliage and not in the potting media. There are root mealybugs that do live in soil, but I have never seen them in orchid potting media. Neither insect crawls very far and transmission is usually plant to plant. If plant leaves touch they will move from one plant to the next, even with water culture.

Less Work

Full Water Culture is less work. You can leave the plant for a month between watering, but you also have to wash out the glass container from time to time, which adds work. I spend 5 minutes per plant, per week. Do you really need to reduce this time?

Semi-water culture is more work than using potting media.

Easier to Monitor Root Problems

This is a valid benefit of water culture. You can easily see the roots and any problems can be dealt with right away.

To some extent the use of clear pots also lets you see the roots in potted plants, but most of them are still hidden by the media.

Since rotting roots are the number one killer of orchids in potting media, seeing them is certainly an advantage. However, if you water correctly and you repot every two years rotting roots are rarely a problem. If the leaves are showing problems it is easy enough to lift the plant out of the pot and examine the roots.

Negative Aspects of Water Culture

Nobody seems to talk about this but there are some significant problems.

• Difficult to support plants.
• Slow process to get plants used to water culture.
• Roots are removed to start the process.
• Fertilizing is more difficult in full water culture.

Difficult to Support Plants

Oncidium Twinkle being held up with string and drinking straws

Root tips are tender and banging them around is not good for them. The normal media in a pot holds the plant in place so it does not move and you can easily add clips after repotting to hold the plant very steady while it forms new roots.

Orchids in water culture are sitting in an open vessel and there is nothing to hold them in place. Phalaenopsis have horizonal leaves that keep the plant from falling into the container, but other orchids grow more vertically and then you need to rig some wire or string to hold them up as in the above picture. In both cases they move around whenever you replace the water or lift the container.

Staking flower stems is more difficult in water culture than in pot culture.

Slow Process to Get Plants Used to Water Culture

Starting plants in water culture is more difficult. You first cut off old roots because they will rot in water. They can be cut off fully or just shortened so they don’t make contact with water. As new roots form they slowly touch the water as they get longer.

If you spend some time on orchid water culture forums you see that many people struggle to get their orchids growing in water, for both full and semi conditions. It is not a simple process, especially for an orchid beginner.

Getting an orchid used to water culture can take 6 to 12 months. Many plants will lose the lower leaves during the process to compensate for the loss of roots. This delays flowering until the plant can get strong enough again.

Compare that to pot culture. Pot up the orchid and water correctly – that’s it. You can even do it when the plant is in flower without harming it, although I try to avoid that.

Roots Removed to Start the Process.

In water culture it is critical to remove any dead or diseased roots because they rot in water. Some people actually suggest cutting off all roots which does tremendous damage to the plant.

It is claimed that the orchid needs to make “water roots”. I don’t know if this is true. Water culture roots don’t look any different but there may be some internal structural or chemical differences. The only study on orchid water culture that I found mentions, “The roots of Doritis pulcherrima (similar to phals) could carry out adaptive growth under water culture condition and new root would grow either from the old root or from the rhizome directly.” This suggests special water roots do grow.

In pot culture you can clean up the roots a bit and remove dead ones while repotting them but even that is not a requirement. The plant will take care of root pruning on its own.

Fertilizing is more difficult in full water culture.

I have done a full review of orchid fertilizer myths here: Orchid Fertilizer Myths – Grow More Flowers.

They need more fertilizer than orchid experts have been recommending but they are also harmed by too much. How do you fertilize in water culture? In the semi method you can dump the water and replace it with new water containing the right amount of nutrients. But in full culture you never know how many nutrients you have in the water. As water evaporates it concentrates the unused fertilizer. As roots absorb nutrients the level goes down. You have no idea how much is in the water and therefore you don’t know if you need to add more.

Under fertilizing results in smaller plants and fewer flowers. Over fertilizing can kill the plant.

In pot culture the excess fertilizer is washed out the bottom of the pot with the next watering making fertilizing easier.

Full Water Culture Trial

I have grown hundreds of species of orchids and at one time had 1,000 different plants. I even won a Best-In-Show award one year, so I know a bit about them. I tried moving a phal into full water culture to experience it first hand.

The roots kept rotting as soon as they spent too much time under water. The plant moved every time I picked up the container – that can’t be good for new root tips. At the end of 6 months, leaves were shriveled and it was dying from lack of roots.

I would never recommend this method.

Phalaenopsis in full water culture. The lower roots in water are rotting. The upper ones that stay drier are fine.

Semi-water Culture Trial

I put another phal into semi-water culture. It has about an inch of water in the bottom. It does dry out from time to time, but there is usually some water in the bottom. The roots and container are all green, covered with algae.

The plant is doing OK and it just started opening some buds. It does not have as many leaves as other plants grown in media. It had some root rot but not as much as in full water culture.

I don’t empty the water every few days – that’s too much work. I just let it evaporate and then replace it. That might build up salts in the container but so far it has not been a problem.

I would not recommend this method either but it does work and it is easier to get an orchid used to the conditions. What I would do is put the orchid in the vessel and just put 1/4 inch of water in the bottom. When this dries up, add some more. Slowly increase the level to a couple of inches. It is best to  dump out the water periodically to prevent salt buildup.

Another Water Culture Trial

This orchid was grown by someone else asking for help on the internet. It has been in water culture for a year and now they are concerned about the yellowing leaves. The lower half of the root system is rotting – you can clearly see the water line. With fewer roots, the plant can’t support the leaves so it is dropping most of them. Normally a phal will lose one leaf at a time as it grows a new one. It does have flowers but the spike does not show a lot of blooms.

This is typical of what I see online from new orchid growers trying to use water culture.

This orchid was in water culture for a year and now shows rotten roots and yellow leaves.

Should You Grow Orchids in Water Culture?

No!

I just don’t see the point. There are few benefits and significant downsides. Pot culture is much easier for the beginner provided you follow some simple watering rules (see above video).

I think that a lot of people have tried pot culture and over watered their plants so they concluded pot culture is difficult. They then want to try something different and water culture works well for many other houseplants. Who has not rooted a piece of plant in water? It is so simple. But orchid roots are very different and water culture for them is not simple.

The industry has also done a great disservice to gardeners by selling potted plants in sphagnum moss. You can make sphagnum work but it is very tricky to get watering right and that is one reason new orchid growers fail. If plants were sold in coconut husk, many more gardeners would have success with them.

The American orchid Society does not even mention water culture on their website. Pot culture has been used successfully for 150 years and has been proven by thousands of growers worldwide.  It is easier to do, grows larger plants, and produces more flowers. Orchid roots need air.

How long should orchids sit in water?

How do you repot an orchid in water?

Can I put an orchid in a bowl of water?