SunGro Soil Evaluation, It’s Definitely Not ProMix!

OK, so that didn’t take nearly as long as we thought. We mentioned we’d give you an update on our thoughts on the new SunGro High Porosity potting soil we’re trying year. We all ready have an informed opinion since the problems set in almost immediately!

While SunGro may look, feel and have a composition similar to ProMix, it’s definitely not ProMix. We’ve all ready observed significant mosses growing and unknown seeds germinating in our germination soils. Worse, though, we’ve all ready been hit by the worst possible thing you can experience in the germination stage, fungal infections. It took about a week and a half for these problems to develop. This is almost always the difference between “premium” soil and knockoffs that might look similar, but definitely don’t perform in a “premium” way.

Now, to temper that opinion with important context. For a long time, we advocated for using sterile seedling soils in the germination process as it practically avoids all of these problems. Established plants really have no issues with these things and plucking an errant seed or scraping some mold isn’t a big deal. But, for baby seedlings, these problems can quickly spell disaster if you’re not immediately on top of it. Baby seedlings are so susceptible to problems, we really can’t be throwing “big plant” problems at them when they’re just trying to get a footing in the world.

We really liked using ProMix because we found that we could use it as both a seedling mix and a regular potting soil, meaning we only had to buy one product. It appears we can’t do that with SunGro’s products, at least without taking on some inherent risk and having to observe things like a hawk. We’d simply prefer not to have to be that vigilant as we’ve had fungal infections wipe out dozens of seedings, practically overnight, in the past.

Sometimes, especially living in Alaska, our choices can be limited and we have to work with what we’ve got. This is the Alaskan way. We haven’t been able to easily acquire sterile seedling soil locally since 2019. For us at least, acquiring ProMix wasn’t in the cards this year either, at any price. So, we’ll have to use our knowledge and adapt.

And how we’re going to do that is to make up a DIY batch of reasonably sterile DIY seedling mix for the rest of the season. This effort hasn’t really been worth it to us in the past, but this development means that it is worth it now. We’ll use this seedling mix in our actual germination process and the SunGro will be used for all transplanting of established plants. And if you’re really trying to understand the methods to our madness, now you have better insight into why we fundamentally disconnect our seed germination and plant growth processes! We have more to say on this in light of our current circumstance, so look for that in a bit.

Very soon, we’ll have a post up on how we do it! And you’ll get to see something we’ve never shown you before! We’re very glad we caught this early, well before we had many hundreds to thousands of seedlings at potential risk!

That’s All We Wrote!

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2 comments… add one
  • VALERIE JENSEN Apr 18, 2024 @ 12:13

    SO SORRY TO LEARN OF YOUR EXPERIENCE WITH SUNGROMIX. When I took the Master Gardener Course under Michelle Hebert, she advised using a mixture of Hydrogen Peroxide diluted in water to prevent damping off and other fungal disease. (She also claimed it sped up germination due to increased oxygenation of the soil.) I recently posted a question about that on the Fairbanks Gardeners FB Group and got SO BLASTED that I deleted my post. Am wondering about your opinion on using small amounts of H2O2 to resolve the issue of contaminated seeding mix. Some of my soil from last year’s WS Jugs are green with mold and I was hoping to re-cycle it by mixing with fresh soil and amendments for this season.
    (1t H2O2 to 1 gal H20)

    • Jeff Apr 20, 2024 @ 11:53

      We definitely know about H2O2 and have it on hand for fungal infections. It does work and its highly beneficial to your plants, since it promotes oxygen in the soil. Some growers will use it, even if they don’t have fungal/algae issues. I would also say that high humidity (and too much water in the soil) can contribute to mold/algae, so sometimes the solution is to decrease humidity as well. So, you can pull a couple of levers to deal with fungal/mold/algae growth and sometimes one or the other is a better approach.

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