By Julie Goldstein
Why buy something when you can easily make it, right? Since the seasons are changing we decided to make some seed starting mix to plant some cool season vegetables in our garden here at CMP. Seeds do best in seed starting mix versus planting them in potting soil, or native soil. Seed starting mix is less coarse, less compactable, and able to retain more moisture than potting soil.
When you search for the perfect seed starting mix, you’ll find many different recipes. I find the easiest recipe (especially when you’re working with kids) is one that includes the following:
- 1/3 Coconut Coir
- 1/3 Sand (or vermiculite from your local nursery if you don’t have access to sand)
- 1/3 finely screened compost or vermicompost (compost/castings from worms)
You’ll often see peat moss listed in seed starting mixes and garden soils. Coconut coir is a more sustainable substance than peat moss and is just as good at retaining moisture and supporting root structure, without the environmental impacts. Peat moss comes from bogs where it’s taken hundreds, if not thousands of years to form, so is not a “renewable resource”. Coconut coir comes from the fiber of the coconut shells so is easily renewable. You can buy coconut coir in brick form from your local pet store that has reptile supplies, or online.
If you are using your own compost, many recommend using compost from a hot compost pile (or one that has reached 140 degrees while “cooking”) in order to kill any weed seeds or plant diseases. If you are worried about it, you can also bake your compost in the oven too. I personally just keep weed seeds out of my compost bin and don’t compost obviously diseased plants to avoid any issues.
Make sure you have a bucket or container for the coir, sand/vermiculite, and compost/vermicompost. You’ll also need a larger container to contain the finished seed starting mix that is high enough that the mixture won’t spill over the sides as the kids enjoy mixing it all up. Since our preschoolers are not very familiar with ratios yet, it’s nice to keep the ingredients in equal amounts (1/3). They can easily grab one handful from each bucket/container in turn or you can assign certain children to different substances. The kids did a great job mixing it all up and made a beautiful finished product! We used it to plant our peas, radishes, carrots, and microgreens! We can’t wait to enjoy them!