Ask Erik: November, 2009
I have one highly productive indoor garden and have been trying different media over my short experience indoors. I am currently using soilless mixes such as coco, sunshine mix and other coco-based mixes but have used rockwool in the past. My question is how can I dispose of such media in an environmentally-friendly manner? I can't use the backyard as the dog has destroyed everything I once grew outdoors! Please help.
Thanks in advance for the great advice!
Sean Kennedy
Usually, it’s okay to mix soilless mixes from indoor gardens into outdoor soils. Typically, used naturally-occurring growth mediums like peat and coco from indoor gardens will improve the texture and introduce some beneficial nutrients, enzymes, vitamins, amino acids, carbohydrates and beneficial microbes into outdoor garden soils. You should allow the soil to “assimilate” the used growth medium through winter months.
Also keep in mind that if you are using products that contain strong plant growth regulators (hormones), this may create some problems. Once introduced into the soil, some of these substances may take a very long time to break down or reach levels that are dilute enough not to effect growth. Remember that you don’t want flowering hormones interfering with the vegetative growth of your garden plants.
It is important to dispose of growth mediums that contain growth hormones in a conscientious manner. If used indoor gardening soils are mixed with a proportionately much larger volume of garden soil, for example 100:1, the effects of any residuals should be minimal.
Growers who re-use organic growth mediums often report that they get healthier plants and bigger yields with each successive crop in the recycled growth medium. When re-using growth mediums, it is a good idea to add a little extra perlite, earth worm castings and lime (if applicable) to re-charge the growth medium between crops. Digestive enzymes and microbial inoculants can also assist in the process.
Alternatively, organic based mediums may be incinerated, as in the case of Sure To Grow and SteadyGRO products. Sure To Grow can be cleanly burned in a biomass furnace. The preferred method of disposal is to remove the subaerial biomass and leave only the root mass behind. The remaining root mass should be allowed to dry out completely and then can be taken to your local plastic recycler. For greenhouses with a bio mass system, SteadyGRO slab media and the entire SteadyGRO block unit can be incinerated for energy purposes. With SteadyGRO, it can be ground up from its original form to a mass of less than 11 per cent of its original volume. Ground up or compacted, the media and left over root volume can be safely placed in your trash bin.
If you are dealing with large volumes of material, you may be able to come to some type of arrangement with a landscape company that can use your spent material as fill or incorporate it into beds, outdoor soils, etc.
Highest Regards, Erik Biksa
