Ultimate Potting Mix in SIPs

[Snaglpus]

Good day, about 4 years ago, I did a test using UPM inside 3 of my large container trees. They were, Galbun, Panachee, and Hardy Chicago. I like UPM. Years ago it was a hot topic! Well I found a supplier and tested it against plain old compost. Hands down, all trees did better in the compost. After repoting 20+ figs (27g 22 in diameter) over the weekend.....Here are my findings..

	UPM	UPM Comment	Mushroom compost Comment	Mushroom compost Comment
Wicking	Excellent	too wet -- uses little water first—on a 90 degree day—you have to water twice a day.	Great	takes time to wick up—you have to water it in layers when you build your pot or your tree will go into shock. Otherwise it could take days to wick up.
Drainage	great	holds too much water for figs	Great	Just don’t block the drain hole
Water Holding	Hold little water	UPM holds little water but more water is needed once it starts to pull.	Hold a lot of water	Can go days without watering due to the density of the dirt
Pros	Very light weight		Very Heavy
Con	Ants love it and will nest in the bottom of your pot—often have to water more over time		To move a 27g SIP that’s 22 inches in diameter is very difficult. Use dunnage or build it only in the spot it will remain for 3 years.

I will not use UPM again. For me, I will be using straight mushroom compost. If you build it right....a tree in a 27g - 22inch diameter pot at 85 degrees only needs watering once a week. But that water reserevoir hold 5 gallons or more of water!

Hopes this helps!

[Harborseal]

Nice report. I'm sure there's a story attached to the drainage hole in the UPM How much does the mushroom compost cost compared to UPM?

[rusty hooks]

Which brand of "Ultimate potting mix" is it...there are several

[Coop]

Nice work Dennis,
I am a fan of mushroom compost too. I only use 100% mushroom compost in my SIP's as Bill's Figs does. It is very heavy but totally works. Very impressive results. I also sprinkle osmocote very generously into the compost when I top it off at the beginning of the season. I also fill up a couple of times a season with some miracle gro. Seems like a good @@@@tail. I do this with my 5 gallon SIP's too

[Kngo436]

Hi Coop, I have my first fig tree in 100% mushroom compost. I stumbled upon Bill's Fig's website but his website said he uses a potting mix. I emailed Bill directly and he said he does not use 100% mushroom compost, he uses 10%. I am now panicking about my fig tree. Can you please tell me if your mushroom compost maintains a moist texture?

[AscPete]

Dennis,
Thanks for sharing this report.
Just took a look at Fertilome UPM potting mix ingredients... Peat 93% to 83% / Perlite 7% to 17% with Limestone and a fertilizer charge, http://www.fertilomesoils.com/ultimate-potting-mix/

Coop suggested a Mushroom Compost from Lowes that contains mostly composted wood mulch (75% - 80%), but mushroom composts are very variable depending on location and type of cultivated mushrooms.
Could you please post any additional info on your brand of Compost or its ingredients? Thanks

[Snaglpus]

Hi Pete,
Here is the best I could do from their website:

Mushroom Compost is a rich dark composted mushroom growing soil that is derived from a mixture of composted products used to grow mushrooms. The compost ingredients include ground yard waste, horse manure, cotton motes, and vegetables. This product is ideal for amending soils prior to planting, top dressing following seeding, and replenishing existing lawns and landscapes. Available in bulk and 1 cu.ft. bags or bulk.

Every day for the past 2 weeks, I've been out repotting many of my trees to SIPs. I have a good feeling about it and I get mine directly from the farm. I tried the compost from Lowes here in Charlotte and it look OK, the problem is it's too expensive for dirt ($3.48 per bag for 1cu ft)! At Wallace, I can get 1 - 1cu ft bag for only $2 dollars! It's pretty cheap! I've already gone through one pallet!

[AscPete]

Thanks for the reply.

[Kngo436]

Hi Dennis, does your mushroom compost feel moist to touch? I have my very first fig tree in a 15 gallon SIP with 100% mushroom compost straight from the mushroom grow houses.

[COGardener]

Has anyone ever compared growing cutting from the same plant, one in ground, one in a SIP and the last in a regular pot? I am finding my self wondering how a side by side by side comparison of the three would pan out.

[AscPete]

Yes. Growth from most to least;
In ground (loam / high organic content)... Best
Potted and partially buried (allowed to root in ground)... Very Good
SIP... Better
Regular Potted... Good

[rusty hooks]

I have an unidentified variety I've been playing with for about 5 years. I think it's a Genoa. 2 years ago I put a rooted cutting of this variety in a 4 gallon sip I concocted out of some materials I had laying around. It took off like a rocket and put on 6 feet of growth last season. I have several in standard pots, some in 5's some in 1 gallons....all have faired well....then this year came. The 4 gallon SIP with 6 feet of growth took a dive...I'm presuming due to a lack of root space and I'm fighting to keep it alive as we type. here's the conclusion I've come to...IMHO....SIP's are great as long as they are of a size large enough for the anticipated tree to remain and grow for 2-4 years undisturbed....that would be a 20-25 or 30 gallon SIP...that way there will be a sufficient quantity of water to last a few days and enough room for the tree to do some growing. Smaller sip's, IMHO...are a bit of a waste of time...although they will crank out some fast results...it's short lived and the tree will end up in a bigger pot sooner or the ground...as I'm about to do this afternoon.

The others in standard pots are somewhat smaller due to the root restrictions but they are healthy and growing well....with the food I'm providing them...they don't get bread and water alone........some of the gallons are now 4-5 feet and will go into some larger pots or big SIP's if I can come to a decision about the moving arragements for the bigger sip's....bad backs and bigger sip's don't co-mingle.

This variety does extremely well in the ground as long as there's an adequate water source. 25-30 feet isn't out of the question...one nearby is where I've "procured" my cuttings and it does fine....no food, no extra or provided water...sits right over an old spring.....and provides figs for all that stop along the way.

[Snaglpus]

Pete, I have to rethink about another method for holding water in tapered pots. I have several 10 gallon pots that I've been using as SIPs. The problem with them is they are 16 inches+ in diameter at the top and taper down to around 10 inches at the bottom. So the normal 3 or 4 inch water reservoir at the bottom isn't working. So, I have to rethink what to place in the bottom to give the trees more water. I'm sticking with pure mushroom compost. To me that the complete best stuff to use! For now, I've been using 3 1/2 inch PVC and wire lathe like what Bill uses. Another issue is these pots have 4 drain hole in the bottom. I got some 3/4 black stoppers tried them but had to seal the bottoms with gutter seal spray and I hope it works!

Any idea what I can use in the bottom of these pots for a water reservoir depth? Maybe 6 inch PVC???? A clay pot? Any thoughts? Here are some pics of these pots. I got them many years ago from Big Lots at a really cheap price.

[AscPete]

Dennis,
Utilizing existing pots with holes or nursery pots as SIPs is relatively simple with a liner of heavy plastic or a piece of Pond Liner... the holes do not need to be plugged because they can also used as the reservoir over flow.

Here is an online description, http://www.insideurbangreen.org/2011...ters-sips.html
and the fabrication of a large sip planter using the liner, http://www.homegrown.org/forum/topic...ed-planter-101

The 6" long PVC sounds like a good idea.... Any non-toxic material that can form the platform support could be used.

[rusty hooks]

This situation is exactly what I'm dealing with right now. the remaining soil or rooting material area becomes relatively small when using longer pvc. I ended up with 2.5" lengths of pvc covered with 1/2" hardware cloth and burl;ap much the same as Bills. Just the other day removed a 6 foot Kadota , one year in a small 4 gallon SIP that had completely filled the water resivoir with roots....since moving it into the ground It has recovered...

From a 1 gallon to a 4 gallon sip doesn't quite give enough room for a years good root growth when a significant portion of the SIP pot is taken up by the res....the burlap had all but disappeared

[Snaglpus]

Thanks Pete and others. I understand now how to rig up these pots. Thanks!!!!!!

Over the past 30 days, I made 65, 27 gallon SIPs using that black drain pipe that Pete referenced. But I tell you the truth....the best soil for these pots is plain ole mushroom compost. When I uppotted my Smith, I didn't use compost and out of all of my 65 trees in 27g SIPs....it's the only pot that's sufferng from sever heat stress. Lesson learned the hard way....

[AscPete]

You're welcome.
Glad to hear that you are having success with the SIPs and the mushroom compost.

I've actually found 2 different types of mushroom compost, the one that Coop recommended which is mostly composted wood mulch and another which is denser and looks like Humus, I believe that its mostly composted straw. I decided to create a Peat based SIP mix simply because I thought that the recommended commercially mixes (mostly peat with some vermiculite and or perlite) were not as well aerated as the figs trees would like and the custom mix could be easily made when needed. The mix uses all the same ingredients as my regular potting mix just at different ratios. The SIP reservoirs are always kept full so that there isn't a need for larger reservoirs or a more water retentive mix.

[Rewton]

Pete, for the SIP design shown in post #10 would you add potting mix into the center of the "donut" made by the perforated drainage pipe and then place landscaping fabric or burlap over the drainage pipe? Or would you simply not change anything and proceed to filling the container with mix? I converted a handful of conventional containers (that already had holes) to SIPs over the winter. They are working well except for one which seems to have developed a leak in the bottom of the reservoir. I am watering that one like a conventional container this season and will repair the problem when the plant goes dormant.

[AscPete]

I create a "Pocket" or "Pouch" out of landscape fabric in the middle "donut" and fill it with potting mix to form the "wick". The landscape fabric that forms the bottom of the aeration platform has a hole cut in its center for this wick. The potting mix is completely contained with landscape fabric (wick and aeration platform).