- Rockwool is a non-degradable medium composed primarily of granite or limestone fibers that are compressed into blocks or cubes.
- They are great for raising greenhouse nursery or hydroponics plants from seeds, stem cuttings, or seedlings until transplanting or up to maturity.
- Ideal for numerous types of plants including tomatoes, lettuce, melons (cantaloupe, honeydew, etc.), cucumbers, peppers, strawberries, zucchini, herbs (basil, thyme, etc.), and cut flowers (petunias, geraniums, etc.)
Features and Benefits
- Great water absorption that supports quick germination and avoids drying out
- Great air retention property – provides seeds and seedlings enough oxygen
- Porous property for optimum water drainage that retains ideal water for plant roots
- Sterile property – free your seedlings from pathogenic microbes
- Non-degradable for up to 3 to 4 years. It can be reused by steam sterilizing between crops.
How to use Rockwool
- Make a hole in the center of the Rockwool cube using a pencil or similar object.
- Sock the Rockwool cubes in water or a slightly acidic solution for about an hour before use. Rockwool come with a pH of 7 to 8. soaking helps to lower the pH to 5.5 to 6 that are favorable for most plants. You can easily prepare slightly acidic water (pH 5.5 to 6.5) by adding several drops of lemon juice into the soaking water and using pH test strips to attain the correct acidity.
- Remove cubes from soaking water and place them in your growing platform and place your seeds, or cuttings into the hole
- Cover the seeds with another layer of soaked Rockwool fibers to prevent drying out and provide heat for germination.
- Place the seeded cubes under a grow light or in a sunny spot and provide a warmth temperature
- Germination usually takes about one week or more depending on the crop types