We’ve been asked many times whether coconut coir can be used for a second crop.
The first question that comes to mind is ‘How clean is your growing operation?’ California Substrates Coconut Coir can happily be used a second time or even a third because it has amazing natural capability, air fill porosity and holds as much water as you want to give it. The potential issue with repurposing or reusing coir in your hydroponic operation is disease. Reusing items like pots carries low risk as they can be washed easily with a strong fungicide or bactericide. Coconut Coir however is a little different. It has a large surface area with lots of nooks and crannies to hold water and nutrients. This makes it hard to be sure that you have killed all pathogens.
Having a pathogen / disease in your crop is like being sick & we know that when we are sick we generally perform less efficiently. Your hydroponic operation & crop is the same way. If your crop gets hit hard, then you’ll think ‘I shouldn’t have reused that coir’ but if your crop gets hit by just a little dose of the pathogen then you may wonder what the problem is. You may not even notice it. Would you notice a 10% drop in production & what does this mean to you?
To be brutally honest, the question of reusing coconut coir with your next crop is an economic one and that question is, ‘What percent of the value of my crop is the cost of the coir?’. The cost of the coconut coir is usually a very small percent of the value of the whole crop.
We worked with a commercial growing operation in Australia primarily growing tomatoes who for years used their grow bags for two crops. One year they ordered grow bags when they should have been reusing the grow bags and we asked them why. They said their second crop in the grow bags was always 4-6% less that the first year and the grow bags were less than 1% of the value of his crop. Easy question. Easy answer.
So in summary, yes, coconut coir can be reused but do you really want to take the risk considering it is only a small cost in relation to the output you will receive.
Personally, we recycle our coconut coir in the garden.
Happy planting ☺