planting for spring harvest

Soil Block VS Potting Tray

Soil block vs potting tray – what’s better? What’s the difference? Who really cares?

We are currently testing both on the farm. We’ve made a great bootstrap soil block maker, we’ve also purchased a soil block maker from Johnny’s Seeds. And, of course, we have some potting trays.

Oh the mysteries of the soil block…what kind of voodoo is this? It’s really not voodoo. It’s science. No it isn’t, it’s physics. Probably not that either – it’s probably me talking out of my ass. Just kidding, soil blocks are actually pretty cool, and they probably are a little bit of voodoo, science and physics and less of me talking out of my ass.

Soil Block VS Potting Tray

Soil Block Madness

Like I said before, we have a bootstrap soil block-maker and we’ve also purchased a soil block-maker. Why? Well, before we decided to invest in a soil block-maker, we wanted to see if it was something we thought would be viable for us. There’s obviously pros and cons. But, does one outweigh the other? For us it did. I personally like the soil blocking idea.

Oh, please tell us your thoughts….I know that’s what your saying in your cute little head. Ok, not really.

Cons:

  • Making soil blocks takes some skill – thankfully you develop that skill quickly. The bootstrap block-maker needs more skill than the purchased one.
  • You will need block “ingredients” on hand and a place to store ingredients
  • You will need flat trays
  • Patience
  • You are GOING to get dirty
Soil Block VS Potting Tray

Pros:

  • Cute little blocks
  • Easy to handle
  • Self-pruning
  • Space saver
  • Easy to plant in
  • Easy to transplant
  • Less storage room required
  • Air circulation around plants

Potting Tray Derangement

Ahh yes, the tried and true potting tray. This is what we know and love as we come home from the local nursery with our favorite, beloved tomato plants. You know exactly the ones I’m talking about – the 6 pack. That’s the one. What could possibly be the cons for these things…just wait.

Cons:

  • Space – these take up a HUGE amount of space if you are using them for seedlings
  • Storage – dedicated storage space until you use them again (if you can use them again)
  • They can be difficult to remove seedlings for transplant
  • Plants are easily root bound
  • Seedlings are more likely to go into “plant shock” upon transplanting
  • If purchasing new trays these can be expensive each year

Pros:

  • Easier to plant a variety of items in one flat or tray
  • Reusable if you handle them carefully
  • Easily available
  • Sometimes free
  • Quick – fill the cell, plant the seed, cover
  • More commonly used in home gardens

That’s our list of pros and cons for each. Let me tell you what I’ve noticed so far in our little experiment. The seeds that I have put into the soil blocks seem to have germinated faster than the ones in the plastic seed trays. Which I personally find interesting. I actually thought the trays would sprout first as they have a little more “insulation” around them (the plastic pot part). I figured they would be a smidge warmer over all and, therefore sprout sooner.

Another thing that I have noticed about our trial, is this. When using seedling trays, I can fit 8 of the 6 pack style pots on a tray. For a total of 48 seed spaces. On a tray the same size, we can put 88 soil blocks. How’s that for space saving?

In conclusion…

Are you ready for my conclusion? Making soil blocks is more time consuming on the front end of seeding. However, you get more use of the space available. They need to be watered from the bottom, so as not to deteriorate the blocks. Transplanting will be a breeze. Dig, drop, cover. Using seeding trays is super easy on the front end. Fill, seed, cover. Big space user. Water from the top, the side, the bottom, it doesn’t really matter. Transplanting can be difficult, you will need to be careful not to destroy your plants or your pots.

Have you started planting your seeds yet? Need some ideas as to what you can plant now? Don’t worry, we’ve got you covered. Check our our post 15 Seeds to Start in February.

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2 thoughts on “Soil Block VS Potting Tray”

  1. Hi folks,

    I see that you are using aluminum sheet pans for your soil blocks. I have been thinking of doing that, too.

    Have you had any issues with them being aluminum? People online worry about phytotoxicity from the aluminum, as well as human health issues from aluminum in the plants they are eating. I don’t know if those are real and legitimate concerns.

    But what great trays they must make for soil blocks. I am thinking of getting the half-sized ones so that they will stay more flat over the years and make watering more even.

    Please let me know what you think of those sheet pans for soil blocks, and especially the aluminum issue (or non-issue).

    Thank you,
    Eric

    1. We’ve not noticed any issues using the sheet pans for soil blocks. That being said, the seedlings move on and off of them pretty quickly once we get started growing.
      They are bakery pans (we bought out a bakery years ago). So, I’m not sure how much (if any leaching) is occuring.
      We think they make great soil block containers. I believe we can fit 180ish blocks on a single tray.
      Peace, love and chickens!

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