Dry LECA
 

I just potted two Zygo's in LECA- my first attempt at S/H. Is it normal (or ok) for the top of the LECA to be dry?

Dry LECA
 

I just potted two Zygo's in LECA- my first attempt at S/H. Is it normal (or ok) for the top of the LECA to be dry?

OK, but not preferable.

There are opposing forces at work - wicking (W) of water up from the reservoir, which is a physical property of the LECA, and evaporation (E).

If E>W, there will be a so-called "dry line" that moves down into the pot, which is less desirable than W>E.

There are several remedies:

• Increase the ambient humidity
• Water more often
• Provide an evaporation barrier of some sort.

Water wicks up the LECA from the reservoir, and evaporates from the top. When the air is very humid, the LECA stays moist all the way to the top. But when it is less humid the water evaporates faster than it can wick up to the top of the container. The lower the ambient humidity, the lower the dry zone will be in the container.

This isn't a problem if the plant's roots extend down into the part of the LECA that is still moist, and you water regularly. But if you put a plant with a short root system into S/H and the humidity is low, you'll need to water every day until the plant grows roots into the moist zone of the LECA.

Ray has posted photos of a transparent plastic disk with a cutout. It fits on top of the LECA around the plant, and prevents some of the evaporation.

Thank you

Awesome-thanks

I've had best luck with the dry line by either increasing the depth of the reservoir, or more recently adding rock wool cubes into the mix in a couple of layers. Raising humidity helps, but isn't always within an easy fix, for me, depending on time of year.

Did you soak your LECA prior to repotting? That also helps.

Thank you

So there is always going to be a dry line, if we imagine a pot that extends infinitely upwards from the reservoir. In my opinion, we want to push that dry line up to a point suitable to the plant. In Ray's S/H system, the the LECA at the base of the plant should always be moist to prevent salt buildup, but in my opinion, some plants enjoy or tolerate a drier climate.

This is why I like a two-pot system. If the roots are shorter, then I could raise the reservoir level (add more water) to raise the dry line. Then, when the roots get longer, I could lower the reservoir as desired. To me, a top dry layer isn't so bad since the salts on the very top of the LECA is unlikely to interact with the plant (but flushing every so often is still advisable).

Using the holes on the side method, you could still extend dry line by using media that's more water retentive near the top, or mixing better wicking throughout. With the latter, it could be adding rockwool cubes as WaterWitchin suggests, or having several polyester/nylon wicks, or seramis, or whatever. With the former, we could add a layer of moss or bark at the top, but this would be venturing a bit further from Ray's S/H prescriptions.

I have found Ray's suggestion of the evaporation barrier to be supremely helpful in my dry enviroment. Such a simple thing compared to humidifiers or watering more often, and it really does make a difference. With virtually no cost if you have suitable material on hand.