Soil Mix Throwdown 2k21

[mgret05]

Tomato-debaters! I'm eyeing three different soil mixes to fill the top ~6 inches of my raised beds. They are each substantially different, and bring different things to the table. What's your vote?

#1. "Happy Hippie Garden Mix" - contains composted forest humus, sphagnum peat moss, compost, perlite, pumice, worm castings, lava rock, humic shale ore, dolomite lime, azomite, soy meal, and gypsum.

#2. "Local Hero Veggie Mix" - contains Sandy Loam, Greenwaste Compost, Rice Hulls, Chicken Manure, Grape Compost, Fir Bark, Cocoa Bean Hulls. This is a favorite of local gardeners.

#3. "5-1-1-ish Mix" - These days I do this for my large planters - 5 parts fir bark mulch (1/4") and ~2 parts mixed manure & green waste compost. I would purchase azomite/rock dust to add. (See below for fertilizers I use.)

#4. This is all wrong, let me tell you what to do.

For reference:
-I'm in Oakland, CA. We don't get any summer rain, and temperatures are moderate.
-I will amend with granular organic tomato fertilizer, fish & kelp emulsion, worm castings, gypsum, maybe azomite. Always eyeing other amendments.
-I'm growing a variety of veggies, but tomatoes are king
-Last year I grew in a standard bagged raised bed mix with lots of compost. I had a ton of pest & powdery mildew issues. Also, the soil has settled a *lot*.
-My raised beds are 12-18" tall, overtop questionable urban backyard soil.
-Mix #2 is the least expensive, but this is all at a small scale and the soils can be bought in bulk, so there won't be a huge difference.
-I don't have many "free" amendments at my disposal - no leaf litter, no space for a compost bin besides vermicompost, and my native soil is potentially contaminated with heavy metals.

Thank you!!

[Gardadore]

#1 has everything I would want, especially Dolomitic lime which I normally have to add for the tomatoes. You wouldn’t need to add worm castings, gypsum or azomite either. Seems most convenient but don’t know cost compared to having to add supplements to #2.

[mama_lor]

Number 2 sounds good. Not sure I would want to use 5-1-1 mix in raised beds, or other very fast mixes, the wicking capacity of the soil under the raised part is huge, it's not a container. Especially if the summers are dry. I don't honestly think you can influence disease much by what soil you have.

[mgret05]

#1 has everything I would want, especially Dolomitic lime which I normally have to add for the tomatoes. You wouldn’t need to add worm castings, gypsum or azomite either. Seems most convenient but don’t know cost compared to having to add supplements to #2.

Yeah, it's got a lot of great stuff! Price is ~$13/2 cu ft bag, which is on the high end for sure. But come to think of it, I already have lime, gympsum, worm castings (on the way, at least, go worms go!). The azomite I don't have. So it might be redundant.

Number 2 sounds good. Not sure I would want to use 5-1-1 mix in raised beds, or other very fast mixes, the wicking capacity of the soil under the raised part is huge, it's not a container. Especially if the summers are dry. I don't honestly think you can influence disease much by what soil you have.

Good point on the wicking capacity of the soil - I hadn't thought of that. The soil holds moisture very well - it's got a good deal of clay but has been improved by sheet mulching and such. So it might be more a source of moisture than a sink...hmm!

[MissS]

Since you have the gypsum and worm castings then I would choose #2. No matter which mix you get there are both soil and airborne pathogens that can cause disease on your plants. The best solution for that is to mulch the soil so that soil and it's pathogens don't splash up on your plants and infect them. Mulching will also help to retain moisture in your beds.

[mgret05]

Update: I purchased a few bags of #2, the sandy loam mix. The mix looks rich, but very heavy. A bunch of sand with a little compost. I could barely move, let alone lift, those 2 cu ft bags! Thank goodness for dollies and my significant other. It seems nice when there's moisture in it, but turns crumbly and hydrophobic if it dries all the way out. I'm going to add some peat moss and another compost source to lighten it up a bit. Fingers crossed!

[bower]

I think you made a good choice with the favorite of local gardeners... they know your conditions better than anyone!
Good luck!

[JRinPA]

I have no idea for Oakland, CA. No summer rain, and temperatures are moderate? For here, that's crazy talk!
I'd suggest to go with the local stuff, assuming you approve of the results others get.

What I use here is landscaper compost. Grass, leaves, and sticks fully composted, with lots of worms in it. Once in a while I'll get a leather glove or an old briggs muffler in there...