Sunday, February 8, 2009

Transplanting the 3/4" soil block into the 2" block

Let's examine the soil block method of transplanting, or otherwise known as "potting on". We call it potting on because you pot "on" top of the next size block. When we transplant, we simply lift one block up and place it on another. No pricking out, which always scares me that I might be ripping some roots out or traumatizing the poor seedlings. No popping out of the container which also seems damaging. And, no untangling any roots that have been circling the pot. Nope, not here. We "pluck" and lift, place and push in slightly to release air pockets. No transplant shock. No stress. However, the potting block method has to be done before the roots overtake the bottom of the block, the only side not air pruned. As you can see in the picture, this tomato taproot has broken the bottom surface and needs to be transplanted. If you were to see the top, the seedling hasn't even produced seed leaves, yet. It is still in it's seed coat, while the root is galavanting around looking for food. That is why we must pay attention to the roots in the Micros versus the leaves. We must have our 2" blocker with cubic pin inserts ready to go and get ready to make some up. We should have made our grow tweezers and be ready to pluck, lift, pot on, push out the air. This ensures a rapid root developement in our seedlings. We now can relax, and watch the growth. We can do this for about 2-3 weeks before we're planting in the garden or planting in the 4" block. Sometimes, growth happens even faster. Say, a week, and we need to tranplant because the roots have maximized the block. So, we stress the need to pay attention to the roots, not the leaves, in soil block transplanting.

It is interesting to note that you can leave tomatoes in the 3/4" block for an extended period of time. Yes, they will be set back a little bit. But, our next move will get them back up. Say, you just didn't get to them in time and they're three inches tall and roots hanging out everywhere and into each others' blocks. We know it happens, especially with that ambitous tomato! You might notice that it would be very difficult to transplant this tomato into a 2" block. It is clearly overgrown. No worries, if you have the 4" block maker! We'll get into making the 4" block next week. If you were to make some 4" blocks and then take your little overgrown seedling and, with a clean exacto knife, cut off all the leaves except the top four. Then, wrap the stem and roots around the micro block, for 360 degrees. A complete loop. At this point, only the top four leaves should be right above that root and stem ball. Now, place in the 4" cube. (The 2" cube can actually work just as well, but make sure you build a strong, wet, fibrous block and push it in.) Back to the 4" cube, simply take some slur and fill in the big 2" hole insert, covering the stem/root ball. Squeeze out the air pocket and let it develop new roots off the stem. After a few days of that, watch out, this 'mato is gonna bust! Try it, you'll have a stronger stemmed tomato that can sit in that block for another 2 months before transplanting.


  1. Thanks so much for sharing your expertise. I just began soil blocking. I sowed my first seed in 3/4" blocks on Feb 2 and I have lettuce, spinach, beets almost an 1" tall. broccoli, carrots and onions are just now showing up.

    Because of room I'll start my tomatoes and squash etc when I get these cool crops into the ground.

    I really appreciate the info on transplanting the tomatoes etc into the 2" blocks when the roots start to show.

  2. Is it possible to start tomato and pepper seeds in a 4" block? I live in a 2b zone and need to start tomatoes and peppers in early April as our last threat of frost is at the end of May.

  3. Andrea,
    Well, it is possible, but not practical and not worth it.
    Why? Because those pepper and tomatoe seedlings need the initial small space to thrive in, as this is proven in Europe to produce the best plants. A little competition for space will provoke the seedling to be aggressive and succeed. Besides that's alot of space to be tied up, like 6-10 weeks in a block. That space could be used to start small batches of seedlings and encourage them to grow better, than sitting in a big block waiting for the weather to be tropical.

  4. Thanks for the info. I am new to soil blocking and will be needing to purchase the appropriate equipment. If you don't mind answering another question...

    How would you start/transplant tomato and pepper seeds if you lived in a 2-3 zone?