You may also compare your new mix to a mix that you are satisfied with. If there is a problem with the mix, you will see it in reduced germination or poor seedling growth (see sidebar). To do a bioassay, grow cress, oats, beans, lettuce, or another fast-growing crop with a high germination rate in your soil mix. Premium potting mixes tested with the saturated paste method recommended for greenhouse media will have a pH between 5.5 and 6.5, soluble salts between 1.5 and 3 mmhos/cm, nitrate nitrogen (NO3) levels between 75 and 150 mg/L, phosphorus (P) levels between 5 and 20 mg/L, potassium (K) between 150 and 300 mg/L, calcium between 100 and 200 mg/L, and magnesium between 50 and 100 mg/L, with sodium contents falling below 160 mg/L (Warncke 1995).Ĭonsider pretesting your potting mix by doing your own greenhouse bioassay. Media sent in as a soil sample is tested differently and results will not make sense. For example, Penn State's Ag Analytical Services Lab has a "Greenhouse Soilless Media" test that will analyze your media's pH, soluble salt (electrical conductivity), and nutrient content. Remember, this is different from a soil test. To test your mix, send it to a reputable lab for greenhouse testing. Mixes made with compost can be high in salts, which can inhibit germination. If you are unfamiliar with your mix or have received a new batch, perform a greenhouse soil test. To prevent delays in your certification, be sure to have material input preapproved by a certifier.
BEST POTTING MEDIUM FOR SUGAR MAPLE TREES FREE
Members of PCO can request a review of any product free of charge. For example, Pennsylvania Certified Organic (PCO) has an internal materials review and publishes a list of materials that they have reviewed and approved. Synthetic wetting agents are not allowed under organic production standards.ĭepending on the certifier, a producer can also request that the certifier review a specific product/ media. Many commercial mixes contain wetting agents to facilitate water absorption by peat moss. It is always best to call your certifier to ensure that using the mix will not compromise your certification. If not, check the OMRI website to see if it is listed. It should state "OMRI listed" on the packaging. Make sure you know what the ingredients are in a commercial mix and check to see if it is listed by the Organic Materials Review Institute (OMRI). Numerous commercial mixes are available for organic growers. However, because organic nutrients are supplied slowly over time, meeting seedling nutrient needs can be difficult. A mix of peat moss, vermiculite or perlite, and compost or organic fertilizers can provide a suitable environment with sufficient water-holding capacity, nutrient content, and aeration for plant growth and development. Most potting mixes are soilless to avoid soilborne diseases and promote good drainage. Potting mixes should support developing seedlings.
0 kommentar(er)
