My Fall Tomato Crop is In - - Now, 27 Container Mix Trials Begin!!

[rnewste]

After a few years now growing in Self-Watering Containers such as the EarthBox and the EarthTainer, I have concluded that there is no "off-the-shelf" potting medium that is ideally suited to the unique needs of a bottom-up, moisture wicking container. Case in point, both the Moisture Meter is pegged in the "Wet" range, and more relevant the plants themselves are more leggy than they should be:



A "symptom" that I observe is early leaf roll which I attribute to a too wet container mix:



Another "telltale" is premature yellowing of lower leaves and branches:



There is also credible evidence that tomatoes grown in SWCs can have a "watered-down" taste. So, how to address the goal of replicating the ideal in-ground growing experience but in an automated self-watering container.

My guideline in selecting a range of materials to experiment with is based on people being able to easily obtain them at big box stores or places that supply lawn and irrigation supplies. Also, ingredients such as Orchid Mix were ruled out due to their excessive cost. As upward wicking is a "must-have" property, mixes such as "Al's 5:1:1" are good for top down watered containers, however I deemed that a SWC mix required a finer particle composition. But the dilemma is that with too fine a particle size, one will end up with "container goo".

So my quest to find an optimal composition of 3 to 4 ingredients that will provide the best balance of moisture wicking coupled with proper aeration for the root system. The products I selected for the trials included:

Sta-Green Potting Mix (Lowes)
Miracle-Gro Potting Mix
Perlite
Cactus Mix (containing Pumice)
Turface MVP
Decorative Bark Fines
Redwood Compost







I had to make some assumptions on a range of combinations and ratios as there are something like 7 to the 6'th Power of combinations when doing the math. So here are the 27 combinations I have planted for the Fall tomato trials.







Miracle-Gro; Perlite
4:1

Miracle-Gro; Cactus Mix
3:1

Sta-Green; Perlite
4:1

Sta-Green; Cactus Mix
3:1

Miracle-Gro; Cactus Mix; Perlite
3:1:1
4:1:1

Miracle-Gro; Bark Fines; Perlite
4:1:1

Sta-Green; Cactus Mix; Perlite
3:1:1
3:2:1

Miracle-Gro; Turface; Perlite
4:1:1
5:1:1

Sta-Green; Turface; Perlite
3:1:1
4:1:1

Sta-Green; Bark Fines; Perlite
2:1:1
2:3:1
3:2:1
3:3:2
4:1:1
4:4:3

Sta-Green; Redwood Compost; Perlite
2:2:1
2:3:1
3:3:2
3:5:2
4:4:3

Sta-Green; Cactus Mix; Turface; Perlite
2:2:1:1

Sta-Green; Bark Fines; Turface; Perlite
2:2:1:1

Sta-Green; Redwood Compost; Turface; Perlite
2:2:1:1

My hope is that a number of these combinations will actually "starve" the plants of moisture and will die. I hope an equal number will also show the leaf roll and premature yellowing leaves, indicating too wet conditions. And ideally, I will end up with a distribution curve of healthy, "just watered enough" plants that will replicate an in-ground experience.

If anyone has suggestions for other combinations and ratios, please post them, as I have 4 more empty 'Tainers for trials.




I'll be posting photo updates and identify the specific container mix with each picture as the Fall tomato crop develops.


Ray

[dokutaaguriin]

Hi Ray,
Thanks so much for all your efforts in fine tuning your 'tainers. We have all benefited greatly from your hard work.
Have you considered using Peat Moss, Perlite and Turface combination? Or any other combination using plain Peat Moss?

Jeff

[rnewste]

Jeff,

I really wanted to stay with ingredients that everyone can easily find. Peat is somewhat more difficult to locate in a decent size bag.

I wanted to "standardize" on Potting Mix (which contains a good percentage of peat), and Perlite as basic ingredients. The other one or two ingredients (and ratios) are to be determined.

Ray

[dokutaaguriin]

Hi Ray,
I thought peat would be easy to find as opposed to a particular brand of potting mix.
I would like to try and mix my own soil next year so that I save some money. I wonder if I'll need a wetting agent for the peat??
Best of Luck with the trials,
Jeff

[Wi-sunflower]

Personally I've used peat, perlite and vermiculite in a 1-1-1 mix for years. While I don't do anything like the earthtainer, I do occasionally do large pots I set in a pan of water and it does seem to wick the water up just fine.

IF you can find clean weed-free sand or sterilize some, adding 1 part does make a better mix. But unless it's sterile, you will get a lot of weeds with the sand.

Personally I prefer the Fafard brand of peat as it's compressed the most and has the least "sticks" so you get the most for your money. Around here several garden centers carry the peat and other stuff, tho I get the best prices when I go to the greenhouse wholesale supplier.

When just starting the mix you need to add a bit of wetting agent or a bit of dish soap like Dawn. OR if you have some time, just water the mix and go do something else for about an hour or so. While the peat may not be totally wet, the vermiculite and perlite will be and eventually the peat will get it from them. As long as it doesn't TOTALLY dry out after that, you shouldn't need much if any more wetting agent.

Carol

[TomNJ]

That is quite an undertaking Ted! Thanks for the huge effort!

TomNJ

[rnewste]

Just a brief photo update. Most of the plants are adding about one inch per day in our warm late Summer weather. For reference, here is a photo taken 10 days ago on Aug 27:



And again today Sept 6:




Here is a pair of Celebrity planted July 21, photo taken today Sept 6. The one on the left is in a 4:1 ratio of Miracle-Gro and Perlite. The Celebrity on the right is in a 3:1 ratio of Miracle-Gro and Cactus Mix:



As you can see, the bottom leaves and branches on the right are wilting at a greater rate than the one in 4:1 Miracle-Gro and Perlite mix on the left.

The Brandywine plant put in on July 21 in a 3:1 mix of Sta-Green and Cactus Mix is showing signs of obvious stress. I attribute this to a too Wet habitat:



Here is a promising mix of 3:1:1 Sta-Green, Perlite, and Turface of 2 Cherokee Purples that were planted on August 3, taken on August 25:



Here is the same pair taken on Sept 6:



Some minor leaf roll, but no yellowing as seen on the adjacent Brandywine plant.

What I am looking for is NOT the plant that grows the most in a "competition", but I am seeking the combo mix that produces a "Christmas Tree" type of top-to-bottom green and healthy plant.

Stay tuned...

Ray

[rnewste]

Received my 4 bags today of 80 Quarts total, which will just about fill one EarthTainer.




This is an absolutely beautiful mix. Reminds me of sleeping on a Goose-down pillow.





Surprisingly (or maybe not so) the listing of Ingredients is EXACTLY the same as Pro-Mix BX:





While the percentages of each are not specified, it does resemble the BX formulation of 82.5% Sphagnum Peat Moss, 12.5% Perlite, and 5% Vermiculite. As an effort to get 2 trials out of this $43 worth of mix, I used the "stock" mix in the right half of the 'Tainer, and did a blend of the Gardener's Supply Mix, Bark Fines, and Perlite in a 4:2:1 ratio (on the left):





I have a bale of Pro-Mix BX on order, so hopefully soon, I will be able to add several more trial combo mixes into the fray....

Ray