HELP! Am I on the right track to make my potting mix?

[tomgirletc]

Hi all, I've been gone a long time but for this big project I decided I need help and best to consult the experts here.

I've done a fair amount reading around and have come up with a mix idea and before I go further I need to know I'm on the right track.

Will be filling 31 Root Pouches, 25 gallons except one 15 gallon. All for tomatoes! I've read about Root Pouches requiring more moisture so I've altered the more simple 5-1-1 a bit to hopefully help in that regard. (FYI, I'll also be using perforated plastic mulch, and then setting up mini-sprinkler irrigation for each pot ultimately which seems like it will cover all the media better than drip.)

3 parts fine wood mulch 1/8 - 1/4" fines
1 part coarse perlite
1 part CoCo Coir (from brick/bale)
1 part horticultural grade Diatomaceous Earth
1 part compost

Also will be adding smaller amounts of this next list of fertilizer type items but HELP MUCH APPRECIATED on approximate right amount for 25 gallon container of each one to give a good nutrient & ph balance. My above mix really only has nutrients in the bit of compost I've planned for.

Kelp Meal (neptune's)
gypsum (espoma)
dolomite lime (espoma)
worm castings
azomite
Tomato Tone (espoma)

Please let me know if anything just seems really out of whack, off track, and why and help me address it.

Thank you sooooooo much! I've got tomato brain for sure , can't wait to get this going!

[shatbox]

That is quite an investment. Have you grown in this mix before?

[tomgirletc]

Nope. It's expensive, but I think still cheaper than buying 105 cu ft of potting mix that may or may not turn out to be a good product and even that I'll need to add plenty of fertilzer and minerals, etc. I'm planning to save the medium for use in the future after doing some sort of solarization, and amending with fresh compost and nutrients each year. I've also found doable prices on everything between local hydroponic stores, internet shopping etc. Of course doing the straight 5-1-1 would be cheaper but I'm really worried about drying out in the Root Pouches and I expect to get practically no rain here. I thought about SWC's but that's also a huge investment and I'm hoping I'll settle on fewer plants in the future and commit to a smaller number of SWC's than the 31 pots I'm going with this year. At this point I can't really remember why I decided to sub Coco Coir for Peat but people seem to really love it and I've noticed Fox Farms and some of the other high end mixes tout their Coco Coir content.

[shatbox]

Because I just got Earthboxes, my mix is based on what is in ProMix BX (which earthbox recommends using). My ratios were 8 parts peat, and one part each of compost and pearlite. I decided to use the extra mix in a few hydrofarm dirt pots (root pouch/smart pots knockoff) with DIY ollas for irrigation.

Last year I used woven poly bags, similar to sand bags, with equal parts wood fines and MG organic potting mix (which strangely had no pearlite. I used a drip (0.5 gal/hr) and had to basically leave it running all day to keep up with the heat. Results were not fantastic.

[Barb_FL]

Just curious, why the Diatomaceous Earth?

Is it possible you choose Coir, vs peat so you didn't need Lime? - ETA - I saw you are adding Espoma Lime.

On the Coir Bricks, I didn't buy the expensive ones. To remove the salts, once it is loose, I put in a blue Walmart cloth Bag /elevate it, and then water it until the color comes out clear or mostly clear. This is done over several days; what I don't use, I leave out for the rain to water.

--
Several years ago, I did the 5-1-1 mix (with Peat though) with Root Pouches. I totally underestimated how much water was needed. My water bills were HUGE; (jumped from $70 to $210). It definitely justified buying Earth Boxes.

To give you an idea how dry it gets, I also added these:http://www.amazon.com/gp/product/B00...garden&sr=1-11.

When I dumped the mix, the spikes were still 100% intact.

ETA - When looking at your amendment list, mine for root pouches is identical except I don't use Gypsum and have been slacking on adding worm castings lately even though I have worm bins. One thing I have been adding a lot of is the Neptune's Harvest Crab shell. I'm doing this for everything including the Earthboxes.

There is a thread on TV re: solarizing; I did it the first time last summer and definitely think it is worth the effort. I will see if I can find the thread and link it.


---
BTW - I'm still a fan of root pouches; I have many for growing tomatoes and peppers. I just don't do the 5-1-1; mostly pro-mix and I elevate everything.

[tomgirletc]

I'm super not excited to see my water bills this summer! I've got two full rain barrels and we will be replenishing with tap water waste from the house (takes a while to get hot water in the kitchen especially). I think I might be able to adjust my mix to be more like Promix if that's better for moisture retention.

[tomgirletc]

Barb-- Glad to hear you are enjoying the root pouches still. After I slim my tomato selection down (hopefully!) I would like to use them for blackberries & melons.

I am using one part Horticultural Grade DE for water retention. It's the "oil sorb" kind that people get at auto parts stores. I have read a lot about it here and other places too. I found a load of it for very cheap so it seemed like a real winner all around.

I am also using Neptune's crab shells, I didn't add it to the list because I thought it was just going to help with the texture of the soil more than anything. I don't think I'm using lots of them but I am definitely going to be adding crab shells to the compost from now on!

I didn't realize that the Coco alleviates the need for Dolomite Lime....should I hold off on adding lime? Thanks for the tip on removing salt...I'll start looking into mine, it was certainly the least expensive stuff I could find so I'll see what I need to do. I have always added both gypsum and lime to store bought potting mix, both to help with BER but I don't know if it was always necessary. Never seemed to hurt as far as I can tell.

I haven't considered epsom for Magnesium much and haven't used it before. Should I?

Thanks for the tip on the Jobe spikes. I will consider for sure if I am watering out ferts like crazy!

So I can still change up my mix to look more like Promix. I haven't yet picked up the Pine Bark fines/fine wood mulch or the compost so those four parts are still pending. The Coco Coir can be changed since the bales are still in plastic and will hold up until I find use for them or I can still use it and add in Peat for 1 or 2 parts. I'll keep the 1 parts perlite and DE in the mix for sure. I can also get more earthworm castings, they would be of questionable quality maybe but I found a fairly inexpensive source. In trying to find out what goes into Promix, I see that they tout their mycorrhizae...it seems buying a bit of the inocculant is not too expensive and I can dab some around the plugs at planting

[tomgirletc]

Shatbox-- so promix ratio is basically 8-1-1? I could totally eliminate pine bark fines/fine wood mulch and sub peat? Therefore 3 peat/1 compost/1 perlite/1 DE/1 coco coir?

[shatbox]

I haven't used my mix yet so I'm not sure how it will perform. It looks close to Promix but doesn't feel like Promix. Promix feels like it has courser materials or more pearlite. I based it off of the PRO-MIX BX Mycorrhizae Information (PDF) and Pro Mix BX Mycorrhizae Tech Info (PDF). It lists the peat content at 75-85% and I ball-parked the pearlite based on the air porosity. I also added 1/2 part vermiculite because I saw it in Promix. I haven't done what would really help figure out the contents, using the saturated weight and moisture content.

I got the 3CuFt Peat bale from Home Depot for ~$13 and a 2 CuFt bag of pearlite for ~$16.

[tomgirletc]

That looks lovely Shatbox -- great job! I'm having trouble finding a better LA source for Peat so far than HD/Lowes. I will be going to Whittier Fertilzer first, then what I don't find there, I'll head to the Big Boxes.

[Barb_FL]

OK - Got you on the DE - I was thinking of the ones for bugs. The kind you are going to use sounds like it will help retain the moisture; so you will start off being close to 3-2-1

RE: Definitely NOT a plug for the spikes in the container; I was just trying to show how dry the mix gets. I haven't used them in containers since and don't buy them anymore. The ones I have on hand go into the raised beds/ground for growing broccoli.

RE: the crab shells, I also put a thin layer of them on the bottom of all my root pouches; then add the mix and never disturb the bottom. I have not seen a pot worm when dumping the mix since doing this.

RE: the root pouches; are you going to put more than 1 plant in the 25 gallon one. I have 2-15 gallons; my favorite size for tomatoes is 7 gallons.

[tomgirletc]

Oh!!! Barb---I see what you meant about the spikes.....the darn things wouldn't absorb because your pots were so dry. Wow! Ha!

No, I am letting the plants be by themselves in the root pouches. I didn't realize that great big tomato plants would do well in 15 gallon ones, and I had only ever done dwarfs in 7 gallons. I haven't seen them in person yet, they deliver on Friday but the measurements on the 25 gallon do not seem so massive compared to old containers that I used. Also, I thought the larger size might be better for water retention.

Good tip on the crab shells in the bottom!

Many thanks to you Barb & Shatbox, this has been very helpful & reassuring. I think I'm going to do at least 2 parts peat subbing for woody fines and I'll get more worm castings I think just because these are a pretty cheap deal I found.

I'll be careful and go easy on the D. lime due to the coco coir part, and I'll eliminate the gypsum. I probably won't need it with the TT fert.

[shatbox]

Whittier Fertilizer uses composted tree trimmings, soil/sand, and no pearlite in almost all of the mixes they sell. Also the little sample boxes in the front do not accurately depict the actual mix for purchase since it is different week to week, month to month and the contents do not get swapped out. Think of it as the ideal.

I bought a cubic yard of the planter mix for raised beds and it turned out, no, ended up being more appropriate for Mediterranean varieties (rosemary, artichoke,...etc) but didn't retain nearly enough water for veggies. Established tomatoes did sufficiently well but nothing compared to those planted in amended, in ground plots.

The compost and "flower and vegetable mix they sell is no different than what the County and City of LA make available for free.

[tomgirletc]

Yes, it is with reservation that I use them and I appreciate your warning! I have used them before so I know to be careful there. What I get from them will not be the bulk stuff, I'll be getting bagged only which for whatever reason I've found is somewhat reliable. I'll not be getting any "mix" from them. Just fine mulch if I use it, peat if they have it at a better price than HD, bagged compost, and worm castings. Questionable quality, but cheap. I question the quality of things at HD too except for the high end stuff but I can't afford to pay for the huge quantity I need of the good stuff. At any rate, they will be my first stop, I'll feel out their selection and prices. I'll get the remainder at HD.

[shatbox]

Let us know what you choose and how it goes!