Vermiculite: Common in many Grow Your Own Cat Grass Kits, Vermiculite is the name of a group of hydrated laminar minerals (aluminum-iron magnesium silicates) which look like mica. Today, most vermiculite is safe. However, that is not to say it cannot contain asbestos. Vermiculite is one of the few retention products to contain asbestos surprisingly NOT banned following the 1970’s controversy surrounding asbestos. Vermiculite is manufactured in various sizes, the smallest of which is used in grow your own cat grass kits. The size of the vermiculite in such kits is hazardous to your cats respiratory system. Should your cat dig and then lick their paws or breathe the dust this could have serious health risks. Read this article for more information. Vermiculite has no nutritional value for the germinating seed. When the cat grass seed has used all the energy stored in the seed for germination it is not receiving any nutrition through the vermiculite. With out nutrition the grass is starting to die. Not a fresh and healthy product to be feeding to your cat!
Coir: Some internet grow your own cat grass kits (and more recently in shops in the UK) contain Coir. Coir is a natural fiber extract from coconut husk. Coir has many applications being used in products such as floor mats, doormats, brushes and mattresses. It is also used for gardening as an alternative to peat moss. It’s Peat Moss like properties makes it a poor growing medium for wheat grass as the high level of water retention prevents growth and promotes mould. Coir has no nutritional value for the germinating seed. When the seed has used all its stored energy it is not receiving any nutrition through the Coir. Without nutrition the grass is starting to die and it has only just grown. Not a grass you would want to be feeding your cat!
Soil is by far the best medium for growing any variety of grass. It’s where Wheat Grass, Cocks Foot, Barley Grass and Oat Grass all grow naturally. It’s what nature intended. Unlike Vermiculite, Coir, or no growing medium (trayed seeds), soil provides the cat grass seed with the nutrients and stability it requires post germination. Once all the energy stored in the seed to grow leaves and roots is spent, the seed uses the roots in the soil to absorb water and nutrients. Using soil as a growing medium means your cat grass will contain all the minerals and nutrients we are looking for, and as a result last much longer as it is still growing and being fed. Soil also has other benefits to growing your own cat grass; naturally preventing mould and ensuring root and leaf separation to permit ventilation.