With Spring right around the corner, many of you might be getting ready to start your seeds. In the past I have always been a dump soil into whatever bucket I can get a hold of kind of person. This led to me over crowding my greenhouse with buckets and containers that I may or may not use to start my seeds in. It became too much for me to store when all I really wanted to do was fill up my greenhouse with plants, not plastic pots! Soil blocking is a great way to save time, money, and space. I tried it this year and I don’t think I will ever go back!
What is Soil Blocking?
Soil blocking is a method of starting seedlings or growing plants in which small blocks of soil are used instead of traditional pots or containers. Soil blocks are made using a special tool called a soil blocker, which compresses the soil into small cubes or blocks, and typically has a small divot, or dimple, on the top that pre-makes a spot for you to drop your seeds into.
The advantage of soil blocking is that it allows for more efficient use of space, as the blocks can be arranged closely together without the need for extra container space. Additionally, soil blocking can help reduce transplant shock, as the plants can be transferred directly from the blocks to the soil without disturbing their root systems. Soil blocking also allows for roots to be air pruned which creates more roots, a stronger root system, and leads to less root bound plants.
Soil Blocking Saves You Money
Soil blocking can save you money on pots, soil, time, and storage space. My soil blocker is less than 10 inches long by 2 inches wide. All I need to make seedlings are this soil blocker and trays with lower sies to create a LOT of seed starts! I was able to fit 40 two inch by two inch seed starts on each tray you see here resulting in 240 seed starts total. I love the lunch trays because they are food grade plastic, take up very little space, and have a small lip so I can bottom water my soil blocks efficiently. I packed my soil blocks really close together so I didn’t waste any space. I spent $25 on 6 food grade lunch trays off Amazon (I would suggest looking local and used first), and was gifted my soil blocker for Christmas. If I were to purchase the soil blocker for myself, this specific brand (Ladbrooke made in the UK) goes for $45 on Amazon. You can find the soil blocker here and the trays I bought here. My total investment, if I bought them myself, would be about $70 and they will last me for years, if not decades. Plastic post can be reused but a very finite amount of times and can break down and crack. Even if you got 2/$1.25 at the dollar store, it would save you a tremendous amount of money!
Soil blocking uses a significantly less amount of soil than filling pots half way or more (unless you are using tiny plug pots), which further saves you money. Soil blockers come in even smaller soil block sizes for those extra tiny seeds which requires even less soil for more seeds, in less space! My biggest issue, solved by using the soil blocker, was space. I have a fairly small greenhouse where I start seeds and store equipment. I want to fill my greenhouse with plants and seed babies, not a bunch of pots I may or may not use!
It probably goes without saying that using a soil block might be a small learning curve but once you get the hang of it, being able to create four seed homes at one time instead of one, is a huge savings of time!
How do You Use a Soil Blocker?
Using a soil blocker is a simple process, but it requires some preparation and care to ensure the best results. Here are the basic steps:
Choose the right soil: The soil used for soil blocking should be light, fluffy, and free of large debris or rocks. You can use a seed starting mix or make your own by mixing equal parts of coco coir, vermiculite, and perlite. I typically use the yellow and purple bags of Kellogg Garden Organics local mix that says “Potting Mix”. On the back it says it is ideal for starting seeds and I find that it also does really well! I used to use a sterile mix because several of my seeds say to use that but, I found in inefficient and expensive in the long run.
Moisten the soil: The soil should be moist but not wet. Add water gradually and mix the soil until it has a consistency similar to that of a damp sponge. If you can squeeze some water out of it, you have enough. If it is like a soup mix, add more soil in. If it’s too crumbly and wont stay together when you squeeze some in your hand, then you need to add more water.
Press the soil blocker into the soil: Place the soil blocker on the surface of the soil and press down firmly. Twist the blocker slightly to help release the soil block from the rest of the soil. I like to put mine into a bit pile of it and slide it towards me in the bucket to really compact a lot of soil into the squares.
Eject the soil block: Use the plunger or handle of the soil blocker to push the soil block out of the mold. You can do this by pressing down on the plunger with your thumb or tapping it gently on a hard surface. You should end up with uniformed tightly packed squares next to each other with a small divot in the top.
Repeat the process: Make as many soil blocks as you need, spacing them out on a flat surface. Then plant the seeds in the small indentation in the top of each soil block. Plant one or two seeds in each indentation and cover with a thin layer of soil or vermiculite.
Care for the seedlings: Keep the soil blocks moist but not waterlogged, and provide them with adequate light and warmth. I water with warm (not hot) water on the sides of my trays and they seep right into the bottoms of the soil blocks for bottom watering. If I find my tops getting dry, I will mist them liberally or I will water them with my watering can lightly. If the blocks get too dry they will crumble apart and if they get super soggy they might also start to fall apart. Once the seedlings are established, they can be transplanted directly into the garden or into larger containers. With the 2″ x 2″ I do not find the need to up-pot them to a larger area, only their final destination when they are big enough!
As always, don’t forget to label your plants!
