Potting Soil Question

[Gardeneer]

vermiculite is moisture absorbent. As it does, expands in volume.
If you want better drainage and add perlite, adding vermiculite is defeating the purpose. JMO
If I want tp improve moisture retention but not compromise drainage I would add floor dry , a baked DE sold at auto parts stores. I have used UltraSorb (from O'Reily )brand in my 511 mix in the past.

[AlittleSalt]

Gardeneer, that is a very good definition of how perlite and vermiculite work. Thank you .

Our upcoming winter's forecast is for above normal temperatures and below normal precipitation. The thought of not using either vermiculite nor perlite is something I have been considering as well.

The table the six 5 gallon buckets of carrots growing in them will be sitting on is located about 20 feet away from an open-faced barn. We can put them inside if there are prolonged days of rain. They won't get as much sunlight in the barn, but they'll still get enough.

The MG product we bought today is soaking wet. It rained about 2 inches last night. Tomorrow, I'm going to open the bag and put it in 5 gallon buckets just to see how long it stays wet. I have around 3 weeks or so to find this out before soil temperatures get down to the 50-65F range that carrot seeds germinate well in. I've read that they will germinate in soil temperatures between 40F and 85F. Here, if you sow most seeds in 85F soil temperatures - you're just wasting time, effort, and seeds. Yesterday, the soil temperature was still 77F here. I will check it again Sunday after a few nights in the upper 50s and low 60s.

I should know if I need vermiculite, perlite, or neither in a few days.

[Worth1]

Salt I soak mine in a big tub before I use it.

Worth

Originally Posted by AlittleSalt

I've been wondering about this for a couple of years now. In the buyable plastic sacks. What is Potting Soil used for?

I don't mean Potting Mix, Starting mix, Garden Soil, Pro Mix, or any of the specialty mixes. Just the one called "Potting Soil". It doesn't matter what brand - what is potting soil used for?

When I was growing up, it was our go-to soil for houseplants, and it worked great (in fact, we probably still have potting soil from the '80s in the middle of our pots). (I don't know what brand/s we used.) I'm not sure that it's designed for outdoor vegetables, unless it says so, though.

I'm not sure that potting soil really has a definition, but I had the impression it was for houseplants.

[Gardeneer]

If something is called "POTTING" soil, the it should be other than just plain SOIL or TOP SOIL.
If then it is good for potting, it should be fine for garden or raised bed.
It is easy to make your own potting mix/soil. If you can get pine bark fines ( <+ 3/8" in size), peat moss, perlite, FloorDry then you can mix your own.(roughly 50% pine bar, 30% peat moss and 20% other stuff) . Some people mix good home mad compost too but then it won't be soil less anymore. Adding soil can cause compaction in pots.

[Fritz77]

Gardeneer, please forgive my ignorance. . I’m also planning on building a raised bed for the next season. It will be an experiment to see if I can get better results. I grow on clay soil and I have a hard time managing it. I’ve read all kinds of theories regarding what kind of soil mix or potting soil you should use. Regarding your recipe (50% pine bark, 30% peat moss, 20% perlite/other), I don’t understand why you should use perlite in this case but I read that almost everyone reccomends its use for potting mix. I just don't understand why. From the little I know, the only real reason why you should use perlite is to allow better drainage and avoid suffocation of the roots in case the soil is too compact. Now, if the rest of the mix is mostly made of Pine bark, haven’t you just reached that goal already without needing the use of perlite?
Another question: if you don't want to add any compost what kind of nutriments would you recommend for a raised bed filled with your “Gardeneer Mix”?

Thanks

Dami

Originally Posted by Gardeneer

If something is called "POTTING" soil, the it should be other than just plain SOIL or TOP SOIL.
If then it is good for potting, it should be fine for garden or raised bed.
It is easy to make your own potting mix/soil. If you can get pine bark fines ( <+ 3/8" in size), peat moss, perlite, FloorDry then you can mix your own.(roughly 50% pine bar, 30% peat moss and 20% other stuff) . Some people mix good home mad compost too but then it won't be soil less anymore. Adding soil can cause compaction in pots.

[dmforcier]

Perlite is a volcanic foam that holds air but does not absorb water. Roots need to breathe, and in wet conditions the air in the perlite provides them oxygen. Perlite is pretty expensive, so 20% may be more than you want to spend. But I'd try to stay above 10%.

Pine bark can become saturated. You use it keep the average particulate size up to prevent the formation of what is known as a "perched water table". Bark vs. other organics like wood chips contains lignite (?) that prevents rotting. Pine bark does not perform the same function as perlite.

Now, the recipe that Gardeneer wrote will drain very well -- maybe too well for your application. Are you in a particularly dry environment?

[Fritz77]

Yes dmforcier. I got it now. Thank you for your explanation. Actually it does make sense. I didn't know pine bark could absorb so much water. As for the costs over here, peat moss could be more expensive than perlite. After all I'm planning on building just one raised bed and it won't be big, so I guess I can afford it.
I just have to find the good recipe.
I don't you could say that I live in a dry area. The average humidity is 70% in the summer.

Originally Posted by dmforcier

Perlite is a volcanic foam that holds air but does not absorb water. Roots need to breathe, and in wet conditions the air in the perlite provides them oxygen. Perlite is pretty expensive, so 20% may be more than you want to spend. But I'd try to stay above 10%.

Pine bark can become saturated. You use it keep the average particulate size up to prevent the formation of what is known as a "perched water table". Bark vs. other organics like wood chips contains lignite (?) that prevents rotting. Pine bark does not perform the same function as perlite.

Now, the recipe that Gardeneer wrote will drain very well -- maybe too well for your application. Are you in a particularly dry environment?

[Worth1]

Raised bed in a not so wet area.
Compost sharp sand, or decomposed granite or both, peat moss, perlite.
The as time goes by just add organic material on top and let the worms do the work.

Worth

[dmforcier]

I don't know that I'd use peat moss for a large volume such as a whole bed if you can't get it cheap. It does degrade and will turn to dust in maybe 3 years, kinda defeating the purpose. Not entirely sure what to recommend in its place, maybe compost? Depends on the amount of water the bed has to shed, and whether it will be isolated from the dirt below, which could absorb water.

From what I've heard, you do want to incorporate organic matter, as Worth says. Have you heard of Lasagna Gardening? Check it out.

[Fritz77]

Like I said, I’m planning on building just one raised bed for experimental purpose. 3-4 plants of tomatoes (Maglia Rosa should be the chosen variety) and maybe eggplants and/or peppers in the future, just to see if they can perform better than what they do in my garden. I grow in a pretty humid area and I was planning on placing the bed on tilled soil, but I could easily use some support and isolate it from the dirt. It shouldn’t be big. I haven’t looked for wood boards yet, but I'm thinking about something like 100 cm x 40 cm (or 40” x 16” in your unit). The height should be around 13-14”. It won’t be too expensive but of course, the cheaper it gets the better it is. So what I could have for free is the following: cupboard/newspapers, compost (not a lot and I have to use it also for the rest of the garden), woodashes, leaves, grass clippings and lots of coffee grounds (would those be of any help?). What I would have to buy is: wood boards, pine bark, sand, hay, straw, perlite, peat moss (quite expensive, Italy doesn’t produce it and it’s all imported from Northern Europe).
Starting from zero, I’ve been reading and studying quite a lot about this method. What I found was controversial or at least complementary information. I guess if people find the time to write a web page or record and upload a video on youtube to describe their fantastic potting mix or their unique raised bed technique,well then it means it works, no matter if it’s the opposite of what another youtuber or gardening forum says. Yes, I read about the Lasagna raised beds (no wonder this technique caught the attention of an Italian pasta lover…). Let’s take this as an example. These are some of the first images you get with a simple Google search. As you can see, the recipe varies a lot, but I guess they are all good.
After all, in my life, I haven’t eaten too many bad Lasagne