Thumbs up for coir!
The weather this season has been trying for home gardeners in Sweden. From incredibly hot weather in May and June without a drop of rain, to downpour after downpour for pretty much the entire month of July and most of August.
This was also the first year we tested mixing coconut fiber (Cocopeat) in the soil of our containers, including the GreenStalks. In previous years, we have mixed perlite in the soil and a few centimeters clay pebbles at the bottom to aid drainage (Tip! if you're using clay pebbles in your containers, enclose them in a mesh bag - they are much easier to reuse this way).
This year we skipped both the perlite and clay pebbles, adding instead 30-40% Cocopeat to the potting mix. Mixing coconut fiber in the growing medium is gaining popularity but not yet widespread, so this was an experiment for us and we were hoping it would not be a mistake.
It wasn't! The result was even better than we had hoped. We noticed right away that we didn't need to water nearly as often as we're used to even on the hottest of days. We could even go away for a few days with nobody to come water and the plants continued to do fantastically well all during the hot dry months. Even the thirsty tomatoes!
The coconut fibers not only hold water, they also make the soil more airy - you can say that it works like the insulation in a house. On warm days, it keeps a cooler climate for the roots and the plants become more resistant to the heat, and cold days the opposite, giving off heat to the fibers. Simply a perfect "U-value" for the plants!
And then came the rain, and we appreciated the coir even more. The Cocopeat was surely maxed out as to what it could absorb already halfway through July but drainage remained unimpaired, allowing excess water to run freely through the entire GreenStalk vertical planter as intended. We did not have a single plant suffering from excess water. Some sun from time to time would have been nice, but we didn't have watering issues 😅
One thing coir doesn't do though is retain nutrients as well as it's equivalent in soil or perlite, so liquid fertilizer (important with all container growing) is extra essential with Cocopeat mixed in, and we were diligent with the fertilizing. Which was easy to do, as it is so quick and easy to fertilize all the plants at once in a Greenstalk.
Will we continue to mix Cocopeat to the potting mix in our container growing? A resounding YES. And happily, we won't need to buy more for several years. Coir degrades very slowly and we expect to reuse this year's purchase for at least 4 to 5 years adding only a small amount more if needed - and some estimate even longer. Our container growing medium is an investment and we reuse it time and time again - the key is to refresh it each season (more on that next Spring).
Read more about best growing medium in a GreenStalk vertical garden