Soil blocks

[Kris Kaul]

Has anyone started seeds using Soil Blocks?  I am trying them for the first time this year, and would love to hear about others' experiences with them. Kris

[Samuel O'Brien]

Yes - they are great, as the roots don't go outside the boundary of the block. I've had great experiences with them when they are made with an actual soil block maker, and not such great experiences when I've tried my own invented technology. I've pretty much followed the guidelines described by Elliot Coleman.

The challenge that I have seen under grow lights is that the blocks dry out a little faster than flats. The benefit is no waste and a more seamless transplant in the spring.

Also, I used them when I had an ample soil supply thawed in a rural area, but find it hard to find a place to keep the right mix ready to block here in Minneapolis. (maybe I need a pole shed?)

S

[d...@thefarmofmn.com]

Kris,    

    Soil blocks are great.  One caution is do not let the block dry out.  The few commercial vegetable grows I have talked to that use these state that is number one priority.   Light misting has to make it to the center of the block to maintain adequate plant growth.  The best part of soil blocks is the air pruning that happens.  This air pruning window is short so watch for the roots at the edges of your blocks.  When they are spotted be ready to transplant them into a larger block or the field.

 

Dan

The Farm of Minnesota

[Kari Wenger]

I like not having all the pots with the soil block method and the plants seem to transfer better.  Ditto on Samuel comment about the mix.  Have not had luck freelancing on Elliot Coleman's recipe.  I use a dust mask when making the mix in the Fall. Thoroughly stirring the complete recipe of about 5 feed buckets of ingredients.  Repeating this process 4-5 times until I fill a metal garbage can full of the soil block mix. If I have leftovers, I just add a bit more of Elliot's "fertilizer mix"the next year. I also use a mask as I am combining the water with the starting mix in the Spring.  For most seeds I start with the mini blocks then plop them into the bigger blocks a week to 2 weeks later.  I teeter between dampening off and overly dry exterior blocks and find moving from mini blocks to standard blocks helpful.  And getting the plants into the ground no more than 4 weeks after starting.  Tomatoes I  pot up after 4 weeks in soil blocks and plant out at 60 days but I am hoping the new hoop-house changes this routine.  

Best of luck,

kari    

[Carol Ford]

Kris, 

I love the vigor of soil block transplants. I've not had the drying out problem others have described but maybe that's because I use either 1) a flat that does not have drainage holes or 2) a flat that does have drainable holes, resting in an older flat that does not have drainage holes. And I start with a pretty wet mix when I'm making blocks. My flats get a bleach water washing before use so I've never had damping off problems.  The flats can be watered from the side so you don't have to water from above, just let the blocks absorb the water that's poured in. For flats that get hardened off outside, that's when the draining flat nested in the non-draining flat comes in handy because I can lift it out after a rain, dump the excess water and put it back in. 

I use the Coleman recipe, with some adaptation. I use the two buckets of compost and instead of a bucket of garden soil, I use either another bucket of compost or a half bucket of vermicompost. Gotta be careful with the vermicompost--it's a rich mix and it gets the plants up and going fast so I use that mix for later transplant seeding, like in late March. An earlier, I find that transplants can get too leggy, but the heavy feeders like tomatoes and cabbage really love a shot of vermicompost .

I've got the room to plant directly into my 2"X2" blocks, so I don't mess around with the little guys. I have a friend who grows annual flowers for sale and she swears by the little blocks for germinating. I think it depends on your operation. I'm small time (12 winter shares) and I've got greenhouse space in spring, so I just go for the bigger blocks. Will be starting leeks next week.

I have also experimented with a couple of other things. At the Milwaukee urban farm, Growing Power, they use a soil mix that is equal parts coir (ground up coconut husks) and vermicompost for just about everything they do. This has worked really good when I'm growing pea shoots in flats but not so great with the blocks. It doesn't seem to bind as well as the Coleman mix using peat, so the blocks can't take much handling until the transplants have established adequate root systems to hold their blocks in place. I haven't noticed a difference in the mature plants but that could be because I also incorporate vermicompost into my beds outdoors so they all get the benefits of that soil amendment in the end. 

I also found that the dust generated from mixing soil is easier to deal with when I'm using vermiculite rather than perlite. I'd be interested to hear the opinions of others because I really have a strong preference for vermiculite. It doesn't create a white dust on my eye glasses, for example. And am I the only one bugged by that green stuff that grows on the perlite?

Carol Ford

Garden Goddess Produce

Milan, MN

gardengoddessenterprises.com