Growing in Clay Balls by Bob Lakey

Growing in clay balls

……by Bob Lakey


Growing orchids in a passive hydroponic system, commonly referred to as growing in

semi-hydro using LECA (clay balls – Lightweight expanded clay aggregate) which is an

inert clay material and contains no nutrients. It is easy to use, it’s clean, you can’t over

water, you will have less problems with disease and insect pest’s. And no more re-potting

every two or three years! just pot up to a bigger pot when needed, no more having to

remove old media and probably the only dead roots you will see are the original roots

which didn’t adapt to the clay balls.

For pots, any type of container can be used, clear plastic drinking cups of around 250ml

and up work well as starter pots. Clear take away containers are fine for bigger plants

which will need a 5″ or 6″ pot. With a soldering iron place a couple of holes about 2 cm

from the bottom to create a reservoir, for larger pots allow about 20% of the pot for the


Fertilizer needs to be kept to a minimum, maybe 1/4 to 1/3 strength or maybe even less,

and needs to contain everything the plant needs, mainly calcium and magnesium which

in most fertilizers is present in very low quantities or absent.

Water as much as you like , the more the better as this will keep the clay balls free of salt

build up. The important thing is to try to use good quality water low in salts, and to

resist hitting your plants with high doses of fertilizer and flush with clean water often.

Think of it this way- if you were going to fertilize your orchids every day, how much

would you use?

Some people will have problems growing in clay balls, the number one problem

will be over fertilizing. I know people who have added slow release fertilizer to their

semi-hydro pot then wonder why their orchids are not doing so well…

total disaster! It does take a while for the plants to die so in the meantime as the

orchids are slowly dying, just blame the clay balls!! I know for sure that the people

who are doing it right are achieving excellent results

I really don’t know of any other reason why anyone should fail using this method..

maybe not watering at all?

Start with just a few orchids in this medium and use good quality water, low strength

nutrient and a sharp lookout for any sign of salt build up, you will soon find what works

for you.

Bob Lakey

Rockhampton Orchid Society

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