greenhouses I shade net I hydroponics I aquaponics
The choice of the correct grow media for your specific crop
T
oday we have many different options to choose from. We mention amongst others Wood Shavings (Sawdust), Perlite, Bark, Peat moss and last but not least Cocopeat (Coir). Most of the used materials are of natural origin, bearing a risk in it for contamination with soil-born diseases, weeds etc. This goes especially for Bark and for Peat moss and for Cocopeat as well. So it is important to purchase from a reliable, certified Supplier. I have seen too many cases of grow media (Bark) badly contaminated with soil borne diseases. But for all grow media rules that we need to adjust the Water Management according to the specifications (structure and texture) of the media as well as according to the crop stage.
Requirements The main property of a grow media is the existence of small pores in it mainly for Water holding capacity and very important the presence of bigger pores for air (Oxygen) holding capacity. As mentioned the majority of our media is from natural origin and we have to anticipate the process of decomposing. As the time goes, the media will change its texture due to the mentioned decomposing with change of water and air holding capacity. Wood shavings option Wood shavings are usually easy available, and if you choose for a courser option and put it in closed horizontal so-called ‘pillow’ bags with plant holes on top, this results in a reliable and relatively sustainable medium since the shavings in those closed bags have a better water holding capacity than the ones in the
open top bags which are often in the start judged as too dry in the top layer and later in the season all of a sudden very wet in the down part of the bag especially when the finer sawdust is used. The mentioned pillow bags are successfully implemented in cucumbers where even two crop cycles are planted in the same bags before replacing.
The choice of a right grow media is one of the most important choices to make your crop cycle to a success.
lower water holding capacity but with better air holding capacity. Another benefit with courser medium is the easier dry back during overnight and in case of overcast or rainy weather.
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Cocopeat option By far the best option however is Cocopeat since that is the most sustainable choice for most circumstances. It is important to choose for the right mix between course and finer material. In general for Bell peppers we go for the courser mix (60% course/40% fine), tomato 50/50 and English cucumber the finest mix (60% fine). But also we have to take into consideration the Irrigation system. When the water supply is stable and secure, we tend to go for slightly courser material with
Undercover farming I
July/August2020
I Volume 17 No 4 13
