Planting Soil Blocks

April may be my busiest time of year, and I am very late in my posting this month. One of those busy things is transplanting dozens of seed flats full of young plants. It’s now time for many of them to go outside.

My experience with Soil Blocks has been really great. I get very good results and avoid using pots whenever possible, but nothing ever goes as planned. This year I’ve noticed two problems. The first was I used a different brand of worm castings in a few trays. These plants struggled and it looked to me like there was a phosphorus deficiency and I found it necessary to supplement them with some liquid fertilizer to keep them going. The other problem I noticed was that for some of my plants I believe I started them a little too early in the season and by the time they were transplanted some of the lower leaves started to yellow, also indicative of a nutrient deficiency.

traysPictured here are many of my Brassica transplants: three varieties of kale, two broccoli types and a purple cauliflower. These seven trays had been growing in my basement for at least four weeks prior. A week before my transplant date I moved the young plants outside into the hoop house so that they can begin to feel what the outside world is like. This is called hardening-off.

The next step is to prepare the transplanting bed. I first used a hula-hoe or scuffle-hoe to quickly mop up any weeds that had germinated and pull any larger weeds. I then added some humic acid, kelp meal and some rock dust made of crushed basalt. Mix this into the top two or three inches, then rake the bed out flat.

Now I determine spacing, information usually given on the seed packet. I’ve learned that not all seed packet information is the same. I usually also look through a reference book or two and search the internet as well. Your experiences and individual soil conditions will also suggest differences. I do most of this look up during the winter months when I am stuck indoors and document them on my calender.

bedrowFor transplanting, the first step is to determine the plant spacing. Plant spacing is easy, it’s the distance recommended between each plant. Don’t confuse that with seed spacing, you want the final spacing between plants after thinning. I review, but usually ignore the row spacing. Row spacing is how many feet between growing rows if you’re farming, or as many gardeners do scaled-down farming. Pre-industrial gardening is a nearly forgotten art. Most gardeners base their knowledge on the experience of farming and scale that downwards into the garden space. The spacing used for farming is very inefficient and was born out of the need to accommodate a tractor.

For my Brassica’s, I started at the end of the four foot wide bed and measured out two rows for the broccoli and cauliflower, and three rows for the Kale. Please note that the distance between my rows is the plant spacing, NOT the row spacing. You can even go a little smaller if you stagger the transplants in each row. Another thing I’ve learned is to be sure and think about how your going to weed later in the season and to always leave enough room for your favorite weeding tool. I normally space my bed rows no less than 6-8 inches apart. Then I take a stick and carefully draw the rows down the length of the bed to mark them.

Now I extend the measuring tape down the length of the bed and fix it there. Using a hand hoe I quickly dig transplanting holes using the measuring tape to guide the spacing. When you have more than one row in the bed, I alternate the transplant holes. For example, with my kale I used 12 inch spacing and I dug holes down the first row on the foot markers (1, 2, 3, …). The second row I offset the holes by 6 inches (1.5, 2.5, 3.5, …), and for the third row I went back to the foot markers (1, 2, 3, …). This actually put each plant at about 13.5 inches apart. This gives you whats called BED SPACING. In the same space using traditional rows I would have only achieved two rows, not three, and I just increased my yield by 33%.

sbOnce all the holes are created, I decided to insert a small handful of high quality worm castings into each hole and mix it up by hand a little. Then I carefully lowered each block into its new home, but haven’t buried them just yet.

Since this blog is about Biological Gardening, how could I leave that out. I now mix in some beneficial bacteria with several gallons of water and use a watering can to wet each block well. After this I carefully bury each plant up to its cotyledons. The cotyledons were those first two seed leaves that formed after germination.

Since I did this work a few weeks ago now, I can also report how they are doing: The plants with the bad worm castings, have recovered and are now growing well, although they are still behind the others. The plants that were started a little too early are still alive and growing but they did struggle to get through a few light frost. The plants that were started indoors at the appropriate time, are doing amazingly well and are bright, green and happy. Despite the differences, of the 224 brassica plants featured here I haven’t lost a single one.

Why would the plants I started only one or two weeks earlier be struggling from a few light frosts when the others are so nice? Their brix was low because the block didn’t have enough nutrition to support that extra growth time. We can discuss this more in the fall, but a high brix plant is not phased by a little frost, as the extra sugar/nutrition lowers the freezing point of the plant.



Soil Blocks: the Building Blocks of Life

Within the first few days of seed germination the maximum yield for your vegetable plant has already been determined. From that point on any and all types of stress that the plant sustains has a direct impact upon your harvest, be it from the weather, nutrients, water, chickens, children, insects, cloudy days, etc. Thus any effort you make to increase your yield in reality is an effort made to decrease your loss of yield. As garden manager, your role then is to identify ways to reduce plant stress at every possible stage to ensure a bounteous crop of nutrient rich food.

blockerThe place to start your plant stress reduction strategies is during seeding, actually it starts with seed selection but that’s for another time. I quickly learned during my first year of indoor seed starting that there was a trick to accomplishing this successfully. First, it didn’t take me long to realized that I was going to have to replace all my black plastic seedling flats every single year, they sure make those things cheap. It also just pains me to have to buy the same thing over and over again year after year, but what other options were available? A little bit of online research revealed to me another method and no more plastic cells and pots. Instead, the pot can be made of the soil itself, soil blocks!

With soil blocks, my young plants grew more vigorously and were highly resistant to the stress of transplant shock. Also, the seedling roots no longer spiraled out of control at the bottom of the cell or pot, but instead upon hitting the outside air the roots will check their own growth and then shoot off again after transplanting. Additionally, losses due to transplant shock were very rare with almost 100% transplant success. There are however a few new concerns. First, you have to be more careful with watering, the extra soil surface area dry’s out a little faster, but that’s easily managed. The other thing is that it’s more time consuming to build the blocks, but this is one area you can have a big impact on plant stress and its worth the extra time, besides its still winter and it gives me something enjoyable to do.

If you want to try soil blocks here is my method, there are many variations so don’t think this is the only way:

  1. soilblocksPick up the soil blocker of your choice off the internet, you can even find directions for making your own. I purchased a 4-cell two inch block maker and it will last me a lifetime of use.
  2. Pick up several higher quality leak proof seedling flats, still black plastic but reusable every year. Naturally they cost a little more, but the price makes up for itself after only one year. Whatever trays you use its important that they do not leak. All the trays I bought from the big box store’s were junk.
  3. Pick up an equal number of black plastic flats that are perforated, or just melt some extra holes into the ones you were going to throw away from last year. The flats I found at my local seed store were exactly that.
  4. Insert the perforated flat into the leek proof flat. When you want to water your blocks gently pull the top tray out, add water to the bottom tray and reinsert the top tray. Always bottom water your soil blocks.
  5. Make your block mixture. There is a trick to this, if you use the wrong materials, not enough water, or too much water then your blocks may not work out. I use about 80% soil less seed starting mixture, 10% high quality worm castings, 5% rock dust, 5% kelp meal and a bacteria/fungal biological inoculation. Mix with water to the right consistency and start making your blocks.
  6. Space the blocks on your trays so there is at least a 1/2 inch of space between them.
  7. Drop your seed of choice into the small hole at the top. Then for most seeds I take a pinch of the soil less mixture and cover the seed, followed with a squirt from the spray bottle to dampen it.
  8. Cover with a clear plastic dome to create a moist environment and wait for germination.
  9. Drink a nice glass of wine to celebrate your hard work and reduce your own stress.