Donna,

There are a number of threads on this very topic scattered throughout perhaps the first 3 pages of this forum. Raybo is currently testing a large number of mix combos in his homemade EarthTainer design and there are many other users of SWC here including those using commercial units and homemade.

I mention the above only to say I don't think anyone has a 'perfect' mix. One of the reasons for this is that every SWC is different, climates are different, plant water demands are different etc. Even saying use pine bark is vague because it comes in such variable sizes and the size of the particles in the mix directly influence how water retentive it is.

One of the problems those using homemade SWC have discussed is the difficulty in coming up with a mix that isn't too moist. With commercial units like EarthBox and the Gardener Supply boxes and Grow Patch etc. this seems less of an issue, but still can be problematic.

Requirements for a SWC mix are that it be able to wick moisture upward the height of the mix, but that it not be waterlogged. It's a delicate balancing act.

Probably not helping you much ;)

My own mix gets altered a bit each time I make a new batch. I currently make my mixes from pine bark and Turface MVP, no peat. I find that the Turface is an excellent wicker, but also promotes good aeration. Peat is an excellent wicker, but is generally the culprit behind 'too wet' mixes which is why I leave it out. In the past I was using pine bark that was more coarse and had little in the way of a composted portion and with that mix I had to use peat to increase the wicking capability. The bark I am currently using has a significant composted portion which is why I don't currently use peat.

If you were using compost and peat, they would be the ingredients responsible for the mixed results. It's all about the particle size. The smaller the particles, the more water they hold.

Using the ingredients on hand you could experiment with different ratios of peat/perlite, but I wouldn't advise the use of compost as it breaks down so quickly.

Hi folks,

I am actually just about done planting my 27 SWC container mix combination trials. This matrix of experiments includes ratios of: Potting Mix, Cactus Mix, Perlite, Turface, Redwood Compost, and Decorative Bark Fines.

{{gwi:32210}}

I hope to post the details of the trials this weekend.

Raybo

Thank you both for your replies.

I had gone through several threads on the topic and yes, I totally agree that the peat can cause a soggy 'collapsing' soil-less mix. This is why I posted Al's 'modified' mix for SWC's. I was hoping to attract the attention of other SWC growers and that they would share their trials and results.

I know I have to find a way of aerating the mix so that it is substantial enough to support its own weight and yet light enough so that the plant can grow unrestricted. Wicking is obviously important, but I certainly don't want the planters to bend up being soggy.

For the most part, my plants are doing well considering how awful this growing year has been here in central WI. My strawberries, peppers, beans, eggplants, and zucchini are doing wonderfully while the tomatoes have suffered with black spot and blight. My melons have done excellent up until yesterday when I spotted powdery mildew. Of course, while the weather is responsible for most of this, my lax feeding schedule and crowding the plants too closely together has played a role, I'm certain.

justaguy2: I so appreciate your input here. I was using my homemade compost that was quite mature and thus, very fine, so yes...I can see how this could contribute to compacting in the containers. I have never used Turface, nor do I know exactly what it is, but it sure seems to be a popular item in growing mixes here on this forum. I guess I'll have to do some more homework on that.

What I have on hand is peat, perlite, vermiculite and compost, but as I look toward next year's growing season, I'd like to get more things on hand to improve the mix.

Raybo: I have been reading your posts and they were the main reason behind my experimenting with SWC's. So thank you very much for sharing your experiences!

Even without your latest trial results, have you found a decent all-purpose mix for the SWC's? I'm thinking that if I had just a basic formula, I could try and improve on that for my needs. I've never used pine bark, but would be willing to try and find some (kind of late in the season).

Donna H.

Agree with justaguy, Turface and bark seem to be the best ingredients as long as the shape of your container allows it to wick fast enough.

I've used 1/2 peat, 1/4 pumice, 1/4 bark. The first year was ok, the 2nd year, the mix was way too wet, even with restrained hand watering from the top.

A 4:2:1 Turface, bark, peat mix is still doing great on it's 3rd year of use. I believe the peat was unnecessary.
This mix has worked well in a Garden Supply SWC which is relatively shallow. This mix did not work well in a homemade 2 5-gallon bucket design, it was not able to wick fast enough for a tomato plant in hot weather.

donna,

Regarding a "basic all-purpose mix", the short answer is no, I haven't found something out of the bag that is ideal. First, Miracle-gro is a good potting mix for top-down watering, but it does TOO GOOD a job in SWC applications. This is even true when used in my commercial EarthBox.

Sta-Green is more "bark based" in my opinion, and it would be my preference if I was not allowed to mix ingredients to make a SWC mix. I have also heard favorable reports on Pro-Mix BX but alas, it is not stocked in the San Jose area, and it is quite expensive, even if you can get it locally.

While Al's 5:1:1 mix works well for conventional top watered containers, you will need a tailored combo mix to both wick up the moisture, but not saturate the mix to make it too wet. This will not be a simple task - - but hey, there is a lot of good brain-power on this forum to help fast-track a good solution!!

Raybo

Raybo,

Where do you buy your Turface? I believe you are in San Jose, I'm just in the Los Altos area?

best regards

EG,

I buy Turface from Ewing Irrigation in Campbell. They have stores in San Carlos and San Jose which might be closer to you. About $12.50 for a 50 pound bag.

Raybo

Here is a link that might be useful: Ewing Irrigation locations

Raybo - I'm reserving my thoughts on the subject for your future thread, which will be quite educational for all - I'm sure.

EG (the original EG)

emgardener: My SWC's are homemade 3 and 5 gal doubles so with that tall of a container, I can see why wicking is VERY important.

Raybo: If the Sta-Green is more bark based, then wouldn't Al's modified mix I noted above work just about the same? I think where I get a bit confused is when some mixes work well in commercial SWC's and not in homemade ones. Depth of mix being the key here.

Like engineeredgarden, I too will anxiously await the results of your trial. I still have so much to learn...

Thanks for the information, everyone.

Donna H.

Thanks Raybo. The store I bought from went out of business (and they charged me $18.50/50lb bag.)

I have been growing in 5 gal. plastic buckets made into self watering, and useing only rotted oak leaves with plant food to grow vegetables. Every thing that I have tried to grow has been a great success and just as good as that grown in the ground. I am now 90 years old and am limited in what I can grow as I am on oxygen 24 hrs. a day and can only try to grow in 5 gal. self watering buckets. I dont go along with all the different kinds of mix that people use as it is mostly just trying something different. I would like to hear from some that has tried the leaves for soil. DAN

This is a direct quote from Dan in which he describes the results of the soil he is again extolling: "I may not have the over saze [sic] plants and highly productive plants but I dont [sic] have to spend a fortune on soil and chemicals."

With all respect, and I don't mean to be harsh, Dan, but I'm not so sure that's 'great success'. I would suggest to others that they can do a lot better than growing in rotted oak leaves because they're cheap. The soils many of us use have nothing to do with wanting to be different. They're about maximizing results while minimizing effort and headaches. That you don't go along with "all the different kinds of mixes" is fine, because many of us that have a considerable store of knowledge know that growing in rotted oak leaves is likely going to yield results we have to accept rather than than results we want.

Al

Well Al you sure did rake me over the coals as the old saying goes. I have looked it all over and can't find where what you said I said so if you want to write what I wrote please get it right. If you can't get it right please don't try to write about what I write. Thanks for writing about it though. DAN

Dan,

The intent is not to 'rake you over the coals'. You have a method that is working to your satisfaction and I don't think anyone begrudges you that.

To put things into perspective, this is a forum where people sometimes post things reflecting that the potting mix doesn't matter or that a potting mix ingredient known to be less than optimal produces 'fantastic' results.

Some of the time I think the folks saying this are being honest. They may have developed skill over the years in working with the ingredients to the point they can do a really good job with what they grow. Other times these are folks who are happy with their results, but many others would not be happy with the same result.

In the end though, what many of us who post frequently here try to emphasize is that which reflects the best science on the topic. The kind of stuff that if a complete beginner were to follow the advice they would more than likely experience good success even though they don't necessarily understand the 'nuts and bolts' of why it works.

I am happy that you are happy with your methods and also happy that at the age of 90 you are still gardening, I can only hope to be so fortunate.

Still, saying things like 'the potting mix doesn't matter' is factually incorrect according to every reputable source out there including commercial growers who don't wish to spend a cent more than they must to get a salable product to market.

Dan - I didn't rake you over the coals, but you can't have it both ways. I wouldn't say you said something unless you did. It's not in me to fabricate support for the things I put forth on these forums.

Following is the is a verbatim quote from you. Clicking on the link will show the thread context, if you're interested "I dont see what is wrong with useing the same soil over and over. Look at our wild areas and you will see soil growing beautiful forest useing the same soil over and over. Stop contaminating your potting soil with man made junk and chemicals that are not a part of nature, and you can use the soil over many times. I may not have the over saze plants and highly productive plants but I dont have to spend a fortune on soil and chemicals." [sic]

I'm sorry, but you continually promote a soil you clearly admit is not giving your plants the best opportunity to reach their potential. I've argued the point with you that this soil, while it may be perfectly adequate for you, is probably going to give a very high % of growers problems they will not be able to deal with because the problems are inherent.

Comparing a forest to a container planting and decrying "man-made junk" in container soils does illustrate basic misconceptions about container media. I pretty near feel obligated to offer a second opinion and some support for it when you suggest oak leaf mold as a stand-alone ingredient for a container soil, much as I did when the subject of Hyponex soil in containers arose.

Al

Good morning Al. I rotted oak leaves that I got under my own oak tree, and made my own swb to put them in and grow most anything I want in the bucket. At my age that is about all I can do as I am on oxygen 24 hrs. a day and can't get out and garden like I used to a while back. I love growing and eating the results, its fun. I am not trying to be critical of what other people do or grow. I care less about others use for soil but do like to read about their methods and results. I guess that years down the road many people will be doing just as we are today, like trying new stuff, and ways to use it. That is the way it has been in the past and will be the same on down the road. Good luck and happy growing.

Oak leaves are great for growing oak trees.

Great for mulch during the winter, too.

Josh