Ideally we would never have to use a product purchased a store in our garden. A great farmer is one who draws (and replenishes) as many resources from his or her farm as possible. Nevertheless, sometimes a store-bought product is necessary.

General Guidelines

  • Avoid the use of pesticides and fertilizers. Any product with an EPA number on it is subject to the usage protocol of your school district. In most cases, it must be locked up and can only be applied by a certified applicator, a notice most be posted at every school entrance for 72 hours before application, and the site must be vacant for 48 hours after the application of the product. Because of these regulations, compost, compost tea, and a few home remedies are the preferred methods of fertilization and pest management.
  • If your school district does not extensively regulate the use of fertilizers and pesticides, follow these three guidelines: 1) use only organic products. 2) keep them securely locked in a dry location. 3) allow only adults to handle these products.
  • According to organic standards, if raw manure is applied directly to the soil, a set number of days must pass before a crop can be harvested from that soil. If you are growing a crop whose edible portion does not have direct contact with the soil (e.g. peppers), then you must wait 90 days. If you are growing a crop whose edible portion does have direct contact with the soil (e.g. lettuce), 120 days must pass between date of application and date of harvest. Despite these standards, avoid the use of manure in school gardens.
  • Fertilizer dispensing containers should be labeled with the common name of the fertilizer. Never use a food container as a fertilizer container.

Organic Products

Look for the OMRI (Organic Materials Review Institute) label to identify a product as organic. Here are our most commonly used products:

  • Seed Applications: Inoculant increases the population of rhizo-bacteria in leguminous crops. These rhizo-bacteria create little nodules on the roots of pea, clover, and bean crops, and are responsible for fixing nitrogen in the soil. Inoculant powder expires after a season, but the bacteria live on in the soil.
  • Foliar Feeds: If you do not have compost tea, add Fish Emulsion and Liquid Kelp to the water when you are watering in a newly-transplanted seedling. The immediate surge of nutrients provided by these products will help the seedling cope with transplant shock. Liquid Kelp can be sprayed on the leaves of spring broccoli if you notice them turning purple. Purple leaves are a result of insufficient phosphorous uptake. Though phosphorous may be abundant in your soil, the cold temperatures of spring can limit its accessibility.
  • Soil Amendments: After the results of your soil test are known, you may need to alter the pH, Phosphorous, and Potassium levels. Use Dolomitic Lime, Rock Phosphate, and Jersey Greensand, respectively. Revita (commercially composted chicken manure) can be added to soil in lieu of compost to increase Nitrogen levels.

Pest Applications

  • Sprinkle Blood Meal around crops to deter mammalian pests such as groundhogs, rabbits, and deer. It should be reapplied after a few rains to maintain effectiveness.
  • If you notice aphids or spider mites on your crops, spray them with a solution of Castile Soap (1½ tablespoons of soap to one quart of water). Do not use detergent or a stronger concentration of soap as it can damage your crops.
  • If flea beetles become a problem (look for them in late July) Diatomaceous Earth can be applied with a flour sifter. It must be reapplied often and is not 100% effective, so think of it as a last line of defense.
  • The first line of defense against flea beetles is the use of row cover as a barrier. Place an object coated with Tangletrap inside the row cover with the plants so that any flea beetles hatching inside will be attracted to the trap and stick to it.
  • Bt, a bacteria which occurs naturally in the soil, can be sprayed on Imported Cabbageworm. Though naturally occurring, Bt should not be used near children. Therefore it is not recommended for school gardens. Instead, handpick Imported Cabbageworm.

Cover Crop

these are crops sown for the express purpose of turning them under. They are intended to be food for the soil, not food for the consumer. The best cover crops accomplish three things: 1) they outcompete weeds. 2) they reduce erosion. 3) they improve the soil by adding nutrients and organic matter. Here are our favorite cover crops:

  • In mid-March seed Crimson Clover (at a rate of ¼ cup per 12’x3’ bed) on beds that will not be planted until mid-May.
  • A good summer cover crop is Buckwheat. Usually, because plants are growing over the summer in anticipation of students’ return in the fall, buckwheat isn’t very useful in a school garden context. It is very fast-growing, however, and can be seeded in late July/August if a crop in one or your beds fails.
  • In late September, seed Field Peas and Oats (½ cup field peas and 1/3 cup oats per 12’x3’ bed). These will add Nitrogen to your soil, then die during the coldest part of winter. Though dead, the roots will keep the soil structure in place during the spring thaw, then add organic matter back to the soil as they decompose. They do need time to establish themselves in the fall, so do not delay their planting.

A Note On Organic Seeds

Organic produce is not necessarily grown from organic seeds. Farmers who are certified organic are required to look for organic seed in three different sources. If no organic seed is found, conventionally grown seed may be used. For Grow Pittsburgh’s School Garden Programs, we typically use FEDCO Seeds, Southern Exposure Seed Exchange, and Johnny’s Selected Seeds as our three sources. Even though our sites are not certified organic, we order organic seeds whenever possible.

Download a printable PDF: Organic Products