Suggestions For 'Drying Out' Miracle-Gro Potting Mix in a SWC?

[rnewste]

outsiders,

What I have observed is that when I empty an EarthTainer, I get a sulfur dioxide smell, as well as see a high concentration of moisture in the bottom 4 inches of the Miracle-Gro potting mix. I am now on a "hunt" to find a combo mix that is light and airy, so that it won't compress into a dense grow media.

I was hoping the Cactus Mix would keep the blend drier, but it still pegs the Moisture Meter. The Perlite seems to keep the combo mix much more granular than Miracle-Gro alone, so this is promising. Here is a photo of 2 ratios I am evaluating:



So far, I have 'Tainers with 15 different trial combinations of: Potting Mix, Perlite, Bark Fines, Cactus Mix, and Turface. Tomorrow, I am going to try a 2:2:1 mix of Sta-Green potting mix, bark fines, and Perlite in another 'Tainer. Again, the goal is to get a "DRIER" mix in a SWC which I would have thought would have been a simple effort. So far, the Potting Mix does too good a job of wicking water up 12 inches. Who would have thought????

Ray

[Structure]

Looking good Ray "Benjamin Franklin" Newsted

Has anyone tried using cloth wicks? I've seen these used in 2 liter bottle swc but never in a big container. I imagine slitting the aeration bench and sliding in some cotton rags would be easy. It might just wick up the soil to wet again, but it would seem to offer more fine-tuning options than soil cylinders.

I expect to have two empty containers soon. I may experiment. Of course, lacking Raybo's spirit of inquiry, I remain hopeful he'll solve the problem for me....*do'ho*

[rnewste]

Hey structure,

One of the neat things about SWC type containers is that you can "fine tune" the growing media to best suit your vegetable crop. The challenge is to find the best combination of ingredients to get the appropriate moisture level suited for tomatoes. I am down to a 12 square inch orifice for the wicking, and that is having little direct correlation to moisture content of the mix.

Fortunately, we have two decent growing seasons here in N. California, so I can hopefully cut in half the number of years it will take to get the optimal mix ratios sorted out.

Ray

[outsiders71]

Ray,

IMO the bark fines would be the way I go. They are cheaper for the quantity and can last a few seasons. I'm interested however to see how your testing goes to see if my observations are legit.

[rnewste]

outsiders,

I was able to find Redwood Compost today at the local nursery:



The particle size of the Redwood Compost (on the left) is quite a bit smaller than the Home Depot Decorative Bark Fines on the right:





As I have a few EarthTainers left to experiment with (and was able to buy some more Champion tomato plants today at Summer Winds Nursery), I am going to try a 2:2:1 mix of the Sta-Green potting mix, Redwood Compost, and Perlite in one half of the 'Tainer and a 3:3:2 mix of the same in the other half of the 'Tainer.

I am also going to do the same (above) in another 'Tainer substituting the Home Depot Decorative Bark Fines instead of the Redwood Compost to see if the larger particle size of this product makes a difference in wicking properties.

Ray

[sprtsguy76]

Raybo- just a note or two here from my spring trials. I tried a 75% decorative bark mix with very poor results this year, so be careful because to much of that stuff will result in stunted nitrogen starved plants, unless its well composted which it doesn't look like. That stuff will tie up more nitrogen than you could imagine. How's your perlite? I got mine from OSH or Home Desprate and it was really powdery. I found some perlite thats more consistant and way less powdery at Hahns Lighting in San Jose off 280. And I personally like structure's idea for the wicking clothes, what ya think? Just doesn't seem like we can shrink that wick down enough.

Damon

[rnewste]

Damon,

I've reduced the wicking orifice now to a 4" by 3" opening, and the potting mix combos are still getting too saturated according to my moisture meter.

Thanks for the tip on too much Bark Fines. I calculate my 2 trials will be approx 40% Bark Fines in experiment #1 (2:2:1); and 37.5% in experiment #2 (3:3:2).

I am trying to find a combo mix that LOWERS moisture content, which is kind of a strange problem to have in a SWC.

I bought my Perlite at Summer Winds ($11.00 for a 2 cu. ft. bag. Seems it all comes from a packager in Chandler, AZ.

Ray

[sprtsguy76]

Just to be clear, use as much redwood compost as you want but the decorative bark is what you have to watch out for as far as nitro. immobilization. Good luck and I do completely understand your 'mission'.

Damon

[outsiders71]

Ray,

We don't get redwood products out here on the east side of the country so I don't know what to say about that. It is a softwood so it should be ok, as hardwoods is what you want to avoid because of Nitrogen tie up. I personally have used pine bark fines this growing season and I have not noticed any nitrogen problems, however I'm top fertilizing every 2-3 weeks or so with seed meal. My containers deplete nutrients faster than your closed ones.

As far as particle size goes, your redwood fines maybe a little smaller than my pine bark fines. When I was shopping around it was difficult to find what I needed because of package labeling, nobody calls partially composted pine bark "pine bark fines". The bag I got from Lowes was called Rustic Mulch, and it says on the bag from pine bark. I actually had no clue it was the pine bark fines I needed until I glanced at a bag that was ripped open and saw what was in the bag!

[Barbee]

Been following this thread with interest. I planted some lettuces in my Gardener's Supply Co SWC a few weeks ago with MG potting mix since I had some leftover from potting up this spring. I can already tell a huge difference in the amount of moisture it holds compared to the mix I normally use for my tomatoes...bought local thru a tobacco supply store but is very similar to Metro Mix or a very fluffy seed starting medium.
I am planning a trip to the town where the tobacco supply store is next week. I'll go ahead and pick up a couple of bags for this winter and store them. Maybe the bags will have a list of what the ingredients are.

[rnewste]

Barbee,

I have concluded that straight Miracle-Gro Potting Mix (even the version without Moisture Control) does TOO good a job of wicking water in a SWC. Even my commercial EarthBox runs too Wet with it:



So, I am trying to find a mix combo of 3 widely available products that will stay moist, but airy and porous as well. Perlite is a "must" in the compound, but the other ingredient (besides a portion of Potting Mix) is elusive right now.

Ray

[Barbee]

Ray,
This is the regular MG potting mix not the moisture control. And yes, it absolutely holds more moisture than what I normally use. I don't have a moisture meter but when I poke my finger down in there...its WET.
For the record I don't use any type of covering on my tomatoes and I am not using any type of covering on the SWC with the lettuces. So everything is the same except for the soil.
If this tobacco mix I'm buying doesn't have an ingredient list, maybe you can get an idea of the texture of it by photos I'll take and someone can recognize the ingredients or something?