Blog: Indoor Seed Starting — Together We Bloom

We are working under the assumption that you have already picked out your seeds are understand when and how to sow them.

There are countless methods and opinions on starting seeds indoors. We are going to highlight the two methods that we use for indoor seed starting: Soil Blocking and Growing in Plug Trays. We will also briefly talk about soil mixtures as well because (honestly) there are so many options out there and it can feel overwhelming.

Soil Blocking:

You may or may not have heard of Soil Blocking. It has become more popular over the past few years here in the USA. Essentially you use a hand tool (soil blocker) and a wet soil mixture to mold groupings of blocks of soil that stand on their own. You then sow your seeds into these small blocks and grow them on flat trays, carefully watering them so that you don’t dislodge the soil. If you are unfamiliar with soil blocking and want to learn more, our two favorite content creators and educators on this subject are: Blossom and Branch Farm and The Gardener’s Workshop.

Benefits of Soil Blocking: Soil blocks don’t require as much soil as traditional plug trays. They maximize the number of seeds you can start in a small space (the main reason we use soil blocks.) The supplies are compact and easy to store when not in use. Seedling ‘air prune’ instead of getting root-bound, allowing them to produce healthier roots. This also makes them a great option for those plants that don’t like to be transplanted. The seedlings are generally faster growing. Depending on your watering setup and your environment, you can transplant the small blocks directly to your soil without having to up-plant them into a larger block or container. If you have poor germination, you haven’t wasted much space under lights or on a heat mat.

Cons/Potential Cons of Soil Blocking: It is more labor and time intensive to make the blocks than it is to fill plug trays with soil (with the exception of the swift blocker- linked under soil blockers that we want.). You will need a fine soil medium which often requires extra sifting. It can have a learning curve in getting the proper moisture levels. Finding and choosing a soil mix can be intimidating. It can still feel like a hefty investment to get started. If your watering setup and environment doesn’t support transplanting the smaller soil blocks directly to soil, up-planting the small blocks can make them more time-consuming than just sowing them into plug trays in the first place. The 2” soil blocks are not ‘space savers’ and generally take up more space per seedling than a plug tray would.

Soil Blockers That We Use: There are several sizes of soil blockers. We use the small (3/4”) soil blocker to seed 95% of the flowers and vegetables that we grow on the farm (linked below.) We started out by purchasing the set (linked below) of the small soil blocker and the 2” soil blocker with supplies. We do use the large 2” soil blocker occasionally for things like sweet peas but we don’t generally up-plant our small blocks into the large blocks as many do due to the scale at which we grow and the need to save space under our grow lights. If we do up-plant the small soil blocks, it is generally into plug trays.

Soil Blockers That We Want To Buy: They now make a stand-up soil blocker (linked below.) When we are making thousands of soil blocks in an afternoon, our hands and wrists can get tired. To have another option that changes how we move our bodies would be so nice so this soil blocker is on our wish list. One day we would love to upgrade to the ‘swift blocker’ soil blocking tools an American-made soil blocking tool that allows you to make soil blocks quickly on 1020 trays and with less toll on your body. They also make their own seeding accessories to make the entire process speedy.