Planter mix for SIPs

[Allyn]

I have been using Mel's mix - one part peat moss, one part coarse vermiculite and one part of a five-part compost -- for my containers. It's the recommended mix for SFG. So far, I'm happy with it, but I'm going to set up a few SIPs in five-gallon buckets. I understand that compost doesn't wick (but the container mixes I've seen recommended for SIPs do contain some compost) and I'm wondering if I can add more peat to the mix I have and have it wick properly. I guess it would end up being two parts peat. What do ya'll think?

[imafan26]

I use Miracle grow potting soil in my self watering containers but the link below has a recipe for potting mixes for self watering containers.

https://homeguides.sfgate.com/create-pot ... 35114.html

[Allyn]

Thank you for the link. Do you think I can take my mix and double the peat moss and have it work okay?

[albopepper]

I have been using Mel's mix - one part peat moss, one part coarse vermiculite and one part of a five-part compost -- for my containers. It's the recommended mix for SFG. So far, I'm happy with it, but I'm going to set up a few SIPs in five-gallon buckets. I understand that compost doesn't wick (but the container mixes I've seen recommended for SIPs do contain some compost) and I'm wondering if I can add more peat to the mix I have and have it wick properly. I guess it would end up being two parts peat. What do ya'll think?

One of the most tried and true methods for growing in SIPs is the Earthbox system. This is what they recommend for an SIP mix: https://earthbox.com/approved-for-earthbox

What you are trying to do is a different approach, but it might work out. One of my viewers recently posted this partial feedback: "I have used Mel's Mix (from Square Foot Gardening) in 5 gallon wicking buckets last year with great success. It is 1/3 manure, 1/3 vermiculte and 1/3 peat moss, and I didn't have any wicking issues and never needed to fertilize."

So you might be able to just use the regular Mel's Mix. I would NOT bump up the Peat Moss ratio though. You need good aeration just as much as good wicking. Throwing in a little perlite would add pore spacing. You might want to consider that.

Or you could even try a couple set ups. Document what you use in each one. And then see what works best. Then share your results with the community!

[imafan26]

I agree. You want a material that wicks well so the compost and peat moss is good for that. The media in my self watering pot is always heavy, but since there is an air gap between the soil and the reservoir I have not had issues with the roots not getting enough air. The soil though does smell anaerobic when it comes out of the container. The plants do seem to grow well anyway. I think they get used to growing in those conditions.

I think it would be a good experiment to see if your soil mix works out.

[Allyn]

Good info! Thank you albopepper and imafan26. With the mix already at 1/3 vermiculite, do you think I still need perlite, too? I thought they basically did the same thing.

I thought to add more peat moss because there's a lot of compost. You think the amount of peat I have is okay then? This is what I keep seeing: "The growing media should be peat-based (70%-80%) that contains perlite or vermiculite." If I increase my peat moss to two parts, it'll be a 50 % mix. That even seems a little low.

[applestar]

I'm new at this as of this year, so I'm very curious to learn how your experiment turns out

[rainbowgardener]

No, perlite and vermiculite don't do the same thing. Vermiculite has a texture more like fine sand and it holds a lot of water. Perlite is much better for improving drainage, keeping channels open for water and air.

[albopepper]

Good info! Thank you albopepper and imafan26. With the mix already at 1/3 vermiculite, do you think I still need perlite, too? I thought they basically did the same thing.

I thought to add more peat moss because there's a lot of compost. You think the amount of peat I have is okay then? This is what I keep seeing: "The growing media should be peat-based (70%-80%) that contains perlite or vermiculite." If I increase my peat moss to two parts, it'll be a 50 % mix. That even seems a little low.

I agree with rainbowgardener in that perlite is a little different from vermiculite. COARSE vermiculite would be the ideal form of vermiculite to use. But even still, it seems to suck up & retain water at a higher level than perlite. For that reason, I would personally be trying out 2 quarts of perlite per 5 gallon bucket. But like I said, there's a gardener who claims that 1:1:1 Mel's Mix worked great for them.

It's super hard to advise people about using compost in SIPs because compost has no single set of properties. Peat moss, generally speaking, is peat moss. It is predictable. But compost can be composed of just about anything, which is why it might or might not work well.

But if you try it with your approach, the compost will be your nutrient source, not a fertilizer. So reducing the ratio of compost to peat moss will reduce your level of fertility. This will not hurt your SIP system, as long as you have good pore spacing. But you might have to ph balance with a little dolomitic lime. And you might need to add organic fertilizer or else water with teas, etc.

Hope that helps, rather than confuses.

[imafan26]

I use perlite instead of vermiculite because of that very reason. Perlite does not hold as much water and the larger sizes are better for creating air spaces. It is also a lot cheaper and easier to find here.

My self watering container instructions originally said to add 2 cups synthetic fertilizer or 3 cups organic fertilizer as a band on the opposite side of the plant. In my case I planted a tomato.

The first time I did that, the tomato grew well, but there was a lot of fertilizer left in the container.

So I switched to 1/2 cup of synthetic fertilizer, or 1 cup organic (tomato tone), as a band and side dressings at first flowering, first fruit and monthly thereafter. I ended up using about the same amount of fertilizer but there wasn't a pile of fertilizer left in the container in the end so it used the fertilize more efficiently.

Never put manure in containers, it has killed every plant when I have tried it. Homemade compost does not work well in containers either and I usually don't add more than 20% by volume, I can add more if the compost I am using is vermicast. Vermicast doesn't seem to bother anything, and I add it if I have it to my potting mixes.

[albopepper]

Never put manure in containers, it has killed every plant when I have tried it. Homemade compost does not work well in containers either and I usually don't add more than 20% by volume, I can add more if the compost I am using is vermicast. Vermicast doesn't seem to bother anything, and I add it if I have it to my potting mixes.

I personally agree with imafan26's approach. I make my own compost & it all goes in my raised beds. Not my containers. But worm castings are a whole different ball game! I've grown seedlings (from seed) in SIPs that were filled with 50% worm castings. The plants were very happy.

[Allyn]

Well that's clear as ....mud. It's all good info and gives me plenty to ponder. I've been using my Mel's Mix in containers and I've been happy with the results so far. (Of course, now that I've said that, I'll go out tomorrow and find all my plants dead. ) The compost portion of the mix is a five-part compost: household, mushroom compost, cow manure, horse manure and something else, I forget. Either alpaca poo or Zoo Doo, I don't remember. That five-part combination (more or less equal portions) is 30 percent of the mix. I'll give you a report once I see how the plants do. Thank you all for your input and sharing your expertise.

[imafan26]

The multi part combination should be o.k., the compost is combined with the manure so it isn't all manure and it should be aged enough. At any rate it is a worthwhile experiment.