Welcome to the fascinating world of hydroponic gardening. The following instructions will guide you through the process of preparing starter cubes, planting seeds or cuttings, as well as mixing and using nutrient solutions.
Starter cubes are an easy way to start seeds or cuttings. They are used widely in both hydroponic and soil gardening. Starter cubes are made of an inert material, meaning that they provide nothing to the plant and its roots other than support. The material retains some water but doesn’t supply any nutrient unless nutrient is dissolved in the water prior to soaking. There are a number of types of starter cubes, including Rockwool, Oasis cubes, Rapid Rooters, peat pots, and Sure To Grows. The best performer for the last several years has been Rapid Rooters. They are organic, pH neutral, bio degradable and they hold an excellent moisture and oxygen ratio. Peat pots are losing favor among gardeners because they have a tendency to retain too much water and as a result can drown the seeds and seedlings. A new product made from coconut husk is now on the market. It looks and behaves like traditional peat or Jiffy pots but performs much better. Rapid Rooters, Rockwool, Oasis cubes and Sure To Grows all retain water well but also retain enough air so that the medium doesn’t stay too wet.
Preparing the starter cubes varies with the kind of starter cube you are using. Rapid Rooters come ready for use. The Oasis and Peat pot cubes should be pre-soaked with water that is pH adjusted to 5.5-6. The cubes need only to be saturated and then allowed to drain. These cubes are now ready to use. Rockwool has a high pH. As a result they must be pre-soaked with water that is pH adjusted to 5.5. This low (acid) pH solution will balance the overall pH to a level that plants require. The cubes should be soaked for about ½ an hour and then drained. They are now ready to use. If you are planning to use Rockwool, please check out the mini-class which deals specifically with the pros and cons of working with this medium.
Once the starter cubes are prepared you are ready to plant your seeds or cuttings. Most starter cubes come with holes already in them. If yours doesn’t, prepare one by using a bamboo skewer, the tip of a pen or pencil or other similar, CLEAN object. Make a small hole in the top of the cube approximately ¼”- ½” deep. Place the seeds or cutting into the hole and gently cover by lightly packing some of the seed cube material from around the hole over the seed or up against the stem of a cutting.
The seed cubes should be kept moist but not wet and absolutely never allowed to sit in water. The cubes will not require light until after the seeds sprout. Cuttings will require 18-24 hours of light immediately. Seedlings don’t require any nutrient until they have emerged from the cube. Once emerged, you can start giving them a diluted nutrient solution (¼ to ½ strength). Cuttings should be watered with pH adjusted water only for the first three days, followed by a ¼ strength bloom nutrient until roots have emerged from the cube. Once they are ready to go into your hydroponic system, switch to the vegetative formula in the hydroponic nutrient you are using.
Preparing the Nutrient Solution
The nutrient solution is simply water with hydroponic fertilizer dissolved in it. To prepare the solution start with good quality water such as RO (reverse osmosis), spring, well or distilled and then mix in the fertilizer at a rate prescribed by the fertilizer manufacturer. If you are using organic hydroponic nutrients or additives containing beneficial microbials (many root developers) make sure the water you use does not contain chlorine or chloramines. The pH of the nutrient solution is important and must be checked and adjusted with liquid pH adjusters. The pH requirement of the nutrient solution is determined by the type of plant you are growing but a good rule of thumb for setting the pH is between 5.5- 6 for all growing mediums except Rockwool which requires a pH of 5.5. For young plants you need to mix a nutrient solution that is ¼ to ½ of the full strength suggested by the fertilizer manufacturer. After the plants are two weeks old you can then start using full strength nutrient solution. Keep the growing medium moist but not saturated.
Once the seedlings have grown roots out of the starter cubes it is time to transplant the plants. This is simply a matter of placing the plant and starter cube into or on top of your permanent growing medium. This growing medium can be any hydroponic growing medium or even soil.