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Reusing Potting Mix

Posted by ricker1958 NE MS 7 (My Page) on
Sun, Jan 23, 11 at 10:06

I have a huge pile of potting mix (Sta-Green) from last season's SWC's. I want to use it again this season but I'm not sure how to recondition it for use. My question is, what should I add to it (if anything) so that I can use it again? I was thinking of adding some composted manure and pine bark fines, but I'm not sure if that's the right thing to do. Any thoughts would be very much appreciated.

Ricker


Follow-Up Postings:

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RE: Reusing Potting Mix

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Sun, Jan 23, 11 at 12:09

From my perspective, I would skip the manure. There's nothing in it you can't get in a good soluble fertilizer that won't break down into sludge in a few weeks. I would be thinking 'lots of pine bark and perlite'. If it was me, I would use
5 parts of pine bark fines
1 part of your soil, maybe 2 parts, depending on how fine your soil is
1-2 parts perlite, again depending on how fine the bark and your soil is.

I would add 2 tsp of dolomitic )garden) lime to each gallon of soil, or 1/32 cup per cubic foot.

The main issue to deal with is increasing water retention as the old soil breaks down into smaller particles. This doesn't occur at an even rate - the older the soil the faster the particles break down into sizes that more rapidly increase water retention.

If you decide to reuse it anyway, let me know. There is a thread that is aimed specifically at how to deal with soils that retain a lot of water. You'll prolly find some helpful tips in it.

Best luck -

Al


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RE: Reusing Potting Mix

ricker,

I would agree with Al. you want to keep your SWC soil-less mix "Soil-less"! Adding manure screws that all up.

Aeration is a key ingredient to success in a SWC. Getting the perfect balance of aeration, plus upward wicking necessary for the SWC properties to function properly is a challenge.

Here is a telling quote on the Premier (Pro-Mix) website:

"""The process of aeration is one of the most important factors of productivity. Plants absorb oxygen (O2) and release carbon dioxide (CO2) during the respiration process. "Respiring" roots use the sugars made during photosynthesis to provide the energy necessary to drive mineral salt absorption. For most plants, internal transfer of oxygen from the leaves and stems to the roots is too slow to supply enough oxygen to the roots. In order to have good plant growth, the growing media needs to be "aerated", meaning that air exchange between the growing medium and
atmosphere has to provide the plant roots with sufficient oxygen and to remove excess carbon dioxide from the root zone."""

For the dimensions of the 31 gallon EarthTainer, I have found a 3:2:1 ratio of (quality) Potting Mix, Decorative Groundcover Bark, and Perlite together do a pretty good job. This Season, I am doing a full swap-out of the Miracle-Gro Potting Mix combo in all 31 of my EarthTainers, and instead, I am basing my 3:2:1 Grow Media on Sunshine #4 Mix as the primary ingredient.

Photobucket

Where I live, the local Hydroponics Store is selling it at virtually the same cost per cubic foot as Home Depot sells the Miracle-Gro. If I were you, I'd get a bale of Sunshine #4 Mix and blend it in with your old Mix when reloading your SWCs.

Raybo


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RE: Reusing Potting Mix

Al and Raybo, thanks for the input. I've read many of your posts on this forum and I absolutely appreciate your advice. I'm going to try and reuse my mix, incorporating your suggestions. I don't know if I can find the Sunshine #4 Mix in the Columbus Mississippi area where I live, but i can fine pine bark fines and perlite. I only had fair results last year with the StaGreen potting mix and was reluctant to go the same route this year. Thanks and I hope to hear from you again.

Ricker.


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RE: Reusing Potting Mix

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Sun, Jan 23, 11 at 15:13

I have to offer an apology. I misread your post to mean that you wanted to reuse your SWC soil from last year in this year's conventional containers. I don't think the ratio of ingredients I suggested would wick sufficiently because of its porosity. Had I read it correctly, and understood you were reusing it in SWCs this year too, I would have suggested something closer to what Raybo suggested. Maybe something like 5:3:1-2, bark:peat:perlite, which is very similar to what he suggested. Sorry if it caused any confusion.

Al


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RE: Reusing Potting Mix

Al and Raybo, thanks for the input. I've read many of your posts on this forum and I absolutely appreciate your advice. I'm going to try and reuse my mix, incorporating your suggestions. I don't know if I can find the Sunshine #4 Mix in the Columbus Mississippi area where I live, but i can fine pine bark fines and perlite. I only had fair results last year with the StaGreen potting mix and was reluctant to go the same route this year. Thanks and I hope to hear from you again.

Ricker.


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RE: Reusing Potting Mix

Not to be redundant, but I would add in some "virgin" new Media such as Sunshine Mix #4 or Pro-Mix BX. Then, as Al says, supplement that with Bark Fines and Perlite in the ratio he suggests.

Sunshine Mix #4 is available EVERYWHERE at all Hydroponics Shops, as it is a staple of those who elect to grow another type of "Cash Crop".

Do some research on the Premier Website on the various Mixes they offer, and what they recommend. Here is a link to their Pro-Mix BRK bark formulation which approximates my 3:2:1 combo Mix. This is tough to find, but it is an interesting "guideline" as to the formulation their Research came up with.

http://www.premierhort.com/website/profweb/aprofweb/premierpress/archives/spring00vol7-1/apress7-1e.html

Raybo

Here is a link that might be useful: Pro-Mix BRK bark mix


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RE: Reusing Potting Mix

I looked up the Sunshine #4 mix on line and the price quoted was $45 a bag of 3.4 cu foot. I pay that for a yard of Nursery Mix #1 from the local landscape supply which is fir bark, pumice and sand with a fertilizer package for 3 months. Am I the only gardener, confined to a retirement income? Al


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RE: Reusing Potting Mix

  • Posted by jodik 5 Central IL (My Page) on
    Wed, Jan 26, 11 at 10:59

I'm not even retired and I'm confined to spending a certain amount for hobbies, which includes my indoor growing! This is mainly why I rejected using bonsai mixes in packages for my potted plants... it's way too expensive! It's so much more reasonable to buy the items in larger bags or quantities, and mix it myself. I hear ya, Al!


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RE: Reusing Potting Mix

Al,

Don't know where in CA you are located, but if you are near one of these Hydroponics Shops, you will be able to get the Sunshine #4 Mix at $28.00 per 3.8 cu. ft. bale:

http://www.gardeningunlimited.com/location.php

In fact, the deal gets even better. These stores were holding a "buy an $80.00 Gift Card for $50.00" deal recently. I bought 4 of them. So yesterday when I purchased 3 bales of the Sunshine #4 Mix with the gift card, my actual cost came out to be using the $50.00 gift card, plus $4.00 in cash. Bottom line: $18.00 per bale.

Their on-line store (EHYDROPONICS.COM)is still offering the $80.00 Gift Card for $50.00 through January 31. It can be used in their California storefonts as well - not just for on-line purchases. What a deal if you live near one of their locations!

Raybo

Here is a link that might be useful: Sunshine Mix #4 Hydro Shops


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RE: Reusing Potting Mix

Thanks for the link Raybo, it is surprising they have no stores in the northbay, but there are other Hydroponics stores and I will check them out. Al


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