1/29/2016
Treating Your Soil Right
Jennifer Zurko
Right now, you should be in the thick of things in the greenhouse—sowing, transplanting, misting and germinating. And this also means that you and your staff have been busy mixing (for some) and filling pots and trays.
Think back on when your growing media for this season showed up at the door. Was it handled with care? Or just shoved in the corner and opened in a hurry when crunch time began?
It’s not too late to look over the checklist below to make sure that you started with a growing media that will help ensure a good, quality crop. Thanks to Ed Bloodnick, Director of Grower Services for PremierTech Horticulture, you can use these Dos and Don’ts as reminders every season.
Do
• Check with your supplier/manufacturer to be sure that the growing medium formulation you selected is appropriate for the application, crop type, stage of plant development and cell/pot size.
• When ordering and storing growing medium, practice FIFO (First In—First Out) with your inventory to be sure your product is “fresh.” Growing medium that’s aged can perform slightly different than fresh product. Over time, pH can rise, wetting ability can diminish and certain fertilizer elements (particularly nitrogen) can decline as a result of use by microbes found naturally in bark and peat moss.
• Store product out of direct sunlight or tarp product in a dry area free of weeds. Direct sun in summer months can heat the product, causing moisture migration within the package. Avoid areas that flood since water penetration can contaminate the product. Be sure that the storage area is free of weeds since weed seed can adhere to packaging and be introduced at potting/planting.
• Be sure the storage area is free of vermin. Mice, rats and other critters can burrow into product to nest and store seeds, contaminating growing media products.
• Remember to read the product label prior to use. Labels provide important information about the product formulation, ingredients, storage and use of the product. Most manufacturers also print the manufacturing date or a number for quality tracking on the package. Take a picture or save a copy of the label if you need to refer back to the packaging.
• During the winter months, it’s not uncommon to have frozen packages of growing medium when stored outdoors. Allow two to three weeks of warm temperatures in your greenhouse, potting shed or warehouse for the product to thaw.
• If you have product left over from the previous year, test for EC, pH and wetting ability prior to use, as these can gradually change with time. For example, bark mixes can change within six months of manufacturing and peat-based mixes within 10 to 12 months, depending on the storage temperatures. High temperatures (above 85F/29C) have a greater impact, as naturally occurring microbes in bark and peat moss are more active. Cooler temperatures favor storage (below 65F/18C). Aged product can still be used, but may require application of fertilizer and/or a wetting agent after transplanting.
In-house testing with a combination EC/pH meter can confirm if applications are
necessary.
• When potting, add water until the growing medium is slightly moist to the touch. You shouldn’t be able to hand-squeeze water from a sample. Avoid adding too much water since saturated growing medium is heavy and will compact when filling containers.
• If you use products with control-release fertilizer, store in a cool area and use within 30 days of manufacturing. High temperature and moisture in the product can cause release of nutrients resulting in high EC.
• If you pre-fill containers, cover pots/flats with shrink wrap and store in a cool area to avoid drying out. Avoid storage in polyhouses or unprotected outdoor areas.
• If you have questions about the use of the growing medium purchased or you need some technical assistance, contact your supplier. Most growing media manufacturers have technical personnel to answer your questions and assist you to be sure you get the best results from their products.
Don't
• Don’t store product near right-of-ways or areas where herbicides are sprayed to control weeds. Overspray and drift can contaminate growing medium with herbicide.
• In the potting area, sometimes growing medium may find its way to the floor. Do not sweep the floor and add this growing medium to the potting machine. This can introduce pathogens and unwanted fine particles to the growing medium. It’s best to discard product that fell on the floor.
• Be careful to not overprocess your growing medium. If you use a small mixer to break bales or a filling machine, physical properties of the growing medium can be altered from excessive tumbling in machinery. Usually a minute or two is adequate to break clumps of growing medium for filling trays and pots.
• Don’t use a growing medium for the wrong application. For example, plug and seed germination media are designed for small, shallow cells trays. Do not use this type of growing media for large containers or baskets, as they will hold a high amount of water and won’t dry down properly for these applications.
Don't overprocess your growing medium. If you use a small mixer or a filling machine, physical
properties of the growing medium can be altered from excessive tumbling in machinery.
• Don’t sterilize growing medium. It’s not necessary because peat, bark and coir are essentially free of harmful pathogens. Also, any beneficial organisms and bio-additives would be destroyed.
• Don’t reuse growing medium since problems in a previous crop will be introduced to a new crop. For example, used growing medium may contain pathogens from previous crops and the pH and fertility levels may be problematic. Only use new, fresh growing medium when planting crops.
• When transplanting, do not compact growing medium around plant roots. Do not “soak in” and transport plants to the growing area since this can cause compaction of saturated growing medium. Place newly planted containers in the growing area and “water in” to settle growing media around plant roots.
• During the crop cycle, avoid “shallow watering,” as this can lead to uneven drying of containers. Water thoroughly until water leaches from the bottom of the container.
• Don’t add ingredients to pre-formulated growing media, as additional ingredients change the physical and chemical properties. If you need to amend a pre-formulated growing medium, check with your supplier for recommendations of what can be added. They may possibly suggest another formulation more suitable to satisfy your needs.
GT