Homemade potting mix for outdoor pots?

I have peat moss, green sand, perlite, organic fertilizer,molasses and sand. THese ammendments I have left from other projects. Can I use some of these to make my lightweight potting mix? Which ones and how much? I did make that mix for my square foot garden, could I use some of that or is it too dense?

I have a couple of different kinds of seedlings coming up in peat pots. They have one set of leaves but don't seem to be getting anymore. They are just getting taller and spindly. Is there something I need to do?

What kinds of seedlings do you have, when did you plant them, how much light do they get?

Ladybeetle -- I don't have an exact recipe, but I would think you could use a similar mixture for your pots as for your beds.
T
Theresa

Alright. For some reason I thought I read somewhere that 'soil' in the mix would pack down in a container or pot. Isn't that why they make real lightweight potting mixes?Maybe I'll just add more peat moss and perlite.

In the early days of our family greenhouse, we made our own mix. I don't recall the exact proportions -- but we began with topsoil which we had scraped off the ground where we were putting a new greenhouse. We actually baked it in an old gas oven to kill any bacteria and weeds.

That mix worked fine for us for a long time and we had very healthy plants for sale. We added peat moss and perlite -- and I believe some humus (not to be confused with hummus), and slow-release fertilizer along with the soil. That access to our own topsoil obviously ran out after a while -- and we went to commercially prepared mixes because of the availability and ease of use for it. These mixes seldom contain any actual soil -- and the lighter mixtures were easier to tote around than the homemade stuff. The lighter mixture also made shipping it less costly, as you could pack a semi full off "soil" more full with light product. I'm sure there are lots more reasons why growers moved to the commercial soiless mixes --one being that they are more consistent in nutrients (or lack thereof) -- and the growers could supplement nutrition and have better control by using liquid fertilization.

Different growers do things differently, but in the "old days" -- lots of dirt was used, but it was amended to help it hold the water, add some nutrition, etc.

In my own pot plants -- I often mix in my own soil because I grow my plants in the ground --then dig them up and put them in pots sometimes - complete with the some of my garden soil. Also, from another perspective, having a bit of your garden soil in the mix may help the plants to transition to the garden - if your intent is to grow them in the ground after they mature. Just a few thoughts.....

Blessings,
T
Theresa

Ahhhh, makes sense. Thanks Theresa!

Can I ask a question regarding this? Due to an increasingly tight budget there have been times when I have needed to pot/repot plants but could not get the gigantic bag of Miracle-grow that I've always used (but, I'm not married to any of my old ways, as I tend to kill most plants, but am determined to learn how to garden). Anyway, I went to my front garden which I had already torn up, dug up a 5 gallon bucket of soil, took a colander (like the cheap plastic ones you use to strain pasta, and such) and I hand sifted the soil. I set aside what was left over which was mostly some small rocks, old mulch, and a lot of roots from old plants. Now, at this point I have two questions. First, because the soil had been sifted, it was very fine and almost powdery. I have never heard of baking it, but do you think sifting it was enough? I knew if I had some Perilite(sp?) on hand, it would be best to put that in, but I had none. I "tested" the ph by doing the white vinegar and baking soda/water test. Neither foamed, so I assumed it was neutral, but have no idea what the actual number was. I had a small amount of peat moss and added that, although I have no idea if that was the right thing to do. My biggest question, however is-was it right to pull out all of the old plant roots? Should I have left remnants of them in? Are they considered "plant matter"? I'm very confused.

Snail, I know that a good potting mix needs organic matter, stuff that has broken down pretty much and isn't green, so if you think a tiny seed wont mind the "old plant roots" leave them in . But even the potting mixes we use at school have a twig here and there but we pull them out. You see if the roots were real strong in an established plant, and in the ground ,the old roots would eventually break down and the roots have other directions to grow. But in a pot they only have so much space to grow in and you want to give the new plant a running start.. Humus or peat moss is a great additive or even well decomposed compost (homemade) or one from the store. A little vermiculite or perlite can be added to create small airspaces (oxygen) to keep the mix from compacting.The peat or compost will eventually break down again by the end of the season, so you would add that part again along with some nutrients like in the granular form. Oh, if you are going to use soil from your yard, it might not be a bad idea to microwave it in small amounts to kill any pathogens that may harm your seedlings before you add the rest of the ingredients. You might look it up as to how long.

I wouldn't use garden soil in containers, it tends to be too heavy and not drain well enough, and I don't think sifting it is going to change that, it'll just clump back together when it gets wet.

Sand isn't the best ingredient for a potting mix because it works its way down to the bottom of the container and it doesn't have any nutrients and doesn't help hold water. Organic matter meets these needs. As it breaks down, it provides nutrition to the plant.

Usually when seedlings aren't putting on new sets of leaves and are getting spindly, they're reaching for light, so that's the likely problem. If you move them to a brighter area, it wouldn't be a bad idea to also feed them with a watered-down water soluble fertilizer each time you water. Just make sure it's a weak solution because the seedlings are fragile at this state and can burn easily.

In the Container forum, there's an extensive discussion on mixing your own container soils. http://davesgarden.com/community/forums/t/527353/ Pretty much tells you everything you need to know.

Also, here's a good article on sterilizing soil: http://davesgarden.com/guides/articles/view/277/