Clay Balls

collage 7

Growing in clay balls

……by Bob Lakey

Rockhampton Orchid Society


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 pests.


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 reservoir.


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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