Soil Blocks

What's up? 

If you ask what I am up to, I can happily tell you that I've been soil blocking. If you are into gardening you've probably heard of or even used soil blocks yourself. In this post, I would like to share my take on how I make soil blocks.

It should be noted upfront that soil blocking is an ancient technique for growing seedlings. But in modern age, it is popularized by works of Eliot Coleman, which is explained in his book The New Organic Grower. He seems to have drawn a lot inspiration from European farmers, in particular Dutch farmers, so it is quite possible that a lot of people were already using it but perhaps didn't write about it as much as Coleman did.

Soil blocks are made from a soil mixture which is rich in nutrients and fiber. The fiber part keeps the blocks together. There are a lot of soil block mix recipes. The recipe of Coleman himself can be found here. One important problem that I've found in all of these recipes is that they contain many ingredients which are hard to find. If farming is your main business, it is probably worth the effort to follow these recipes to get the best possible results that you can. However, you shouldn't be discouraged if you can't get your hands on some of these ingredients as my experience shows.

In this post, I will share my simple approach and show you the results that I got. Hopefully it will motivate you to do soil blocking if you haven't given it a chance before.

First of all, we need the soil blocker equipment to make soil blocks. I've purchased mine from Ladbrooke company in UK. I believe that they can ship their tools all over the world. The model that I purchased is the 4 compartment mini soil blocker, for which a picture is shown below:

I've later also purchased the micro-20 model, but I use the mini-4 more frequently. It makes 2 by 2 inch (or 5 by 5 cm) soil blocks.

To make the soil mix, I simply use potting soil and coconut fibre, also known as coir. Providing a specific ratio is difficult as I typically do not measure when making the soil blocks.  But I estimate that 1 part of coir is more than enough for about 7-8 parts of potting soil. I mix them in a waterproof and wide container and wet it with water. It kind of looks like this:

It is a good idea to give some time to the coconut coir to absorb the moisture. You can then mix it by hand or by using a small shovel. Actually at this point I sometimes add a little bit of liquid worm castings to give my mixture an extra fertility boost.

The ideal consistency for the mixture is when you squeeze it with your hand it should slightly drip and be able to hold its shape. In the end this is what the soil blocker is going to do. So you can add water to strike such a consistency.

Don't worry if you added too much water -- you can simply add some more coconut coir and/or potting soil to absorb this extra moisture. Once you think that your mixture is ready, all you need to do is use your soil blocker to create soil blocks. For this purpose, simply plunge your soil blocker into the mix to fill it with the mixture. It is a good idea to repeat this process while moving the blocker back and forth inside the mixture to make sure that you thoroughly fill each compartment. You can thoroughly compress the soil and scrape off the extras by sliding the blocker back and forth on the base of the container while applying some pressure. We are talking about a 10 second process, so it is easier done than said (hmm, I think this idiom was the other way around but this is what I mean in this case).

Once the soil is snugly compressed in the blocker, you simply place it on a seedling tray and pull the handle of the blocker to release the soil blocks. I generally try to create the following pattern on a 10 by 20 inches tray:

You may wonder why this empty space? Yes, I could possibly sneak in a few more rows of soil blocks but this arrangements serves me well when it comes to watering. I bottom water using a long nosed watering can and these empty spaces are where I can pour the water on. Because the soil blocks are fragile when they are first made, if I crowd the tray with soil blocks I can easily crumble a few of them when watering. Anyways, this is a personal preference and gives me more than enough soil blocks per tray (40 soil blocks to be specific). This is roughly how they look like when first made and placed on the tray:

At this point, simply put your seeds in the center of each block. The soil blocker makes a small indentation in the center for this purpose. You can put 1-3 seeds depending on the expected germination rate of your seeds. There is no need to cover the seeds with soil, unless the type of the seed requires it to be buried (most common plants such as lettuce, tomatoes, peppers, etc. do not need to be covered). When germinating the seeds look like this:

This is actually another benefit of soil blocks. You can see your seeds germinating and if some of them do not after most of them did, you can simply reseed them. This would be difficult to catch if you covered your seeds with soil.

Enough with words. Below are several pictures of my lettuce germination experiment with soil blocks. You can see that the seedlings look very strong.

To summarize, I really think soil blocking is an excellent way to start your seedlings. The little time you lose when planting is more than regained when planting. Furthermore, your seedlings not only develop better root structure but also do not experience transplant shock. This is because you do not disturb the roots at all when you plant them to your garden. The only disadvantage of soil blocking is that you need to water your seedlings more frequently (probably once a day) as they lose moisture more rapidly due to being open from all sides.

 

So I hope you found this little post encouraging to get you started on your soil blocking journey ...