Hydroponic Growing Medium
There are commercially available growing mixes available that represent excellent value. These will require you to grow the plants in pots and will supply a good, sterile, inert medium that is easy to control and allows for good root formation and aeration. Here we have outlined some of the more popular growing mediums:
Rockwool
One of the most popular growing media for hydroponics is Rockwool. Rockwool is a man-made mineral fibre; the majority of Rockwool is used for insulation purposes however there are many different forms of Rockwell with different mineral content and back in the 1960’s they invented a style that works to promote plant growth. This specially produced horticultural Rockwool is what is primarily sold as a hydroponic substrate. This comes in a variety of sizes, is very convenient to use and is ideal for growing in large trays.
Consider starting off your plants in 1” (2.5cm) cubes. As your plants outgrow these small cubes they fit very nicely into larger cubes without the need to disturb the roots. If you are growing multiple plants you can use Rockwool in slabs.
The best Rockwool is produced from basaltic rock which has a mineral balance that is inert and non-reactive however Rockwool can contain high proportions of metals and may be slightly reactive to the nutrient solution. Be aware that Rockwool naturally has a high pH (around 8.0) so you need to get your Rockwool from a hydro shop. Although, you can neutralise any high pH by soaking your Rockwool in water that you have adjusted to pH 5.5 for an hour or so.
Perlite
Perlite is an amorphous volcanic glass that has been heat expanded and formed into granules. It is pH neutral, is porous, and has excellent water retention and capillary properties. It has a range of horticultural applications being particularly suitable for transplanting cuttings and seedlings; its very light weight also makes it suitable for use with containers. Perlite can be very dusty which poses a threat of clogging to small pumps. If bought from a garden supplies shop it may also have been treated with fertilizers. Always wash perlite before using in a hydroponic system.
Clay pellets
Expanded clay pellets are formed from small round balls of clay which are heat treated, causing them to expand and become porous. They are completely sterile and inert with a neutral pH. They can be sterilized and re-used and provide great drainage and aeration.
Beginner growers are usually better off buying a medium from the store, whether that be brands like Pro-Mix or Sunshine. When you become more advanced you will want to save money by creating your own medium and generally they are created using the same bases such as sphagnum, peat moss or coco coir. To ‘beef’ the volume and create some more air pockets growers like to use lava rocks, wood chips, perlite and vermiculite which will also help keep the roots moist. Coco coir is the fibrous inside of the coconut and is sterilized and dried and due to its form being not too dense or too airy it is a good basis for growing in.
Soil
Good quality commercial potting compost should meet all of your plants’ requirements. It will have the correct texture, water retention and drainage. Some growers like to mix in about 10% perlite, or similar product, to prevent soil compaction and water loss.
Avoid using soil from the garden as this may harbour pollutants and soil-borne diseases.
Discard soil when the grow is completed and replace with new soil for each subsequent grow.
Thank you I have always been intrested in how people grew outdoors and how they knew if their soil was good or not.
I’m impressed how much knowledge and science goes into these plants just goes to show how important it is to know about what you put in your body.
Has any body tried water beads? You can find out more at waterbeads.net. With their dealer program pounds of beads are $16.00 and that makes about 220 cups of beads.
i have tried a few different mediums and the one that works for me is coco grow it is very consistent and the plants really seem to thrive in this type of soil
I got these clay pellets. Do I just stick the Seed in there and let the water flow through them? Wont that wash the seed away?
Great show on horticulture. I am a licensed consultant with the State of California. I feel it is better for your health if you don’t use miracle grow products.If you have any questions, feel free to contact us at 916-475-5397
Ive been using standard car washing sponges, they work a treat.
yes does that include organic miracle grow
what is the best way to water your plants after planting into regular soil i would really appreciate a quick response before i go in to this process head first thanks for all your help