As far back as I can remember I have used plastic or biodegradable seed pots to grow my seedlings. I have even used empty egg cartons, milk jugs and butter tubs, from time to time. I never thought about mixing my own soil and making my own seed-starter blocks, until a friend told me about how much better seedlings grow in this type of environment. Always intrigued about anything gardening, I started researching seed-starting soil blocks on the Internet. What I found was interesting and convinced me to try a different way of growing my seedlings this spring.
Where do you start?
You start with soil. Unlike plastic or biodegradable pots, seed-starting soil blocks are comprised of a soil mixture only. There are no containers to hold the soil. So, if there are no containers, how does the soil stay together? What prevents it from crumbling and falling apart? Moreover, how is this a better growing environment for seedlings?
The soil mixture is usually comprised of sedge peat moss, compost, sphagnum, and perlite. It is mixed with water to a consistency of peanut butter. If you do not want to mix your own, you can purchase bagged soil blended just for soil blocks.
Soil blocks are better for seedlings because unlike plastic or biodegradable pots they do not limit the flow of oxygen to the roots. Reduced airflow in plastic pots will cause roots to become root-bound. Root-bound is when the roots of a plant grow in circles within the pot. The roots of the seedlings will reach the edge of the block soil and not go any further. They will stay in the soil and grow larger, not longer. This creates a larger and healthier plant.
Making the soil blocks
To make soil blocks, you will need a soil block maker. These can be purchased at nurseries or online. They are most often square, come in different sizes, and come in sets. I have seen four, five, six, 12 and 20 individual cells to one soil block maker.
Once you have your soil mixed, you push the soil block maker deep into it, then position it over a seedling tray or other type container and push the plunger down. The soil comes out in neat blocks with a small hole in the top. The holes are there for the seeds. Then you just cover the holes with a little soil and wait for the seeds to sprout.
Removing seedlings from pots when transplanting can cause damage to the seedling and its roots. This does not happen with a soil block.
More articles from this contributor:
How to take care of vegetable seedlings
How to thin indoor, outdoor and container seedlings
Assisting the elderly and wheelchair bound to care for seedlings
Source: johnnyseeds.com