What exactly is garden soil, and why shouldn't it be used for potted plants?

Question

Okay, I searched internet but didn't help much, so here is my question, I hope for a detailed answer.

What is garden soil? I mean, why it is not recommended for potted plants? Is it because it's heavy and doesn't drain well and less to no aeration? Or some other factors also make it a bad choice?

How can one treat or make the clay or garden soil good for potted plants without using Vermiculite, Perlite, Organic matter. Is there any other method?

Personal Experience:

I potted a plant in garden soil and watered the plant with around 3 litres of water. The soil didn't drain any water at all. Yes the pot has enough drainage holes. My Mother and Father said that I watered too much, but I don't think so.

I tried to explain to my Mom that the soil is bad and not good for potted plants, but she still insisted that that was caused by too much water. Then I demonstrated it again, but this time choosing a bigger pot with different soil. I watered the bigger pot with 1 litre of water and the soil really drained much of the water I watered. That's a good soil there.

In a nutshell:

• Pot A: average size pot with garden soil; watered with 3 litres of water; didn't drain any water. didn't drain any water.

• Pot B: Bigger than Pot A but with different soil (not garden soil). Gave 1 litre of water and it drained much of it.

Yet my Mother and Father said the culprit is too much water. Whereas I think the culprit is the garden soil. They said to give a little water (100ML or so) around it.

Which brings to me to the next question: Should I give less water if I am using clay/garden soil (and nothing else) or watering too little is a bad thing to do? What's the case? Can anyone enlighten me here?

Answer 1

I don't know how I managed to post an answer twice...

Many people do use garden soil in their pots - but it's a risk. Bacteria, pathogens, fungi and other bio diverse life forms in open ground may cause no problem and you won't even be aware of their presence/existence. Take the soil and enclose it in a pot,and if there is any pathogen in it, your plant/s may not do well, get sick or even die.

As for the water drainage/soil issue, you are correct - some soils and soil mixes drain much better than others. You know that when you pot a plant up, its usual to water it thoroughly, allow it to drain down, then water when it needs it ongoing. Not giving enough water will mean the plant goes short - but there is some merit in suggesting that clay and silt type soils do hold onto water very well indeed, so giving a little less may not cause the plant to suffer drought, although it may mean plants which don't like heavy, soggy, poor draining clay soils won't do well anyway.

Answer 2

One shovel full of a larger ecosystem and soil profile takes that soil out of context. There are lots of bits 'n pieces but no beneficials normally found in a larger garden system that control the pests. Just one little pest without what is normally found in the garden that you didn't or couldn't pick up to control and balance that soil could mean death of your plant. Plants in the larger garden have a larger palette of beneficials, drainage, organic matter...I mean a real soil profile! No way could a shovel of garden soil have any of the benefits found in the larger ecosystem out of doors. Go look up soil profiles and the importance in soil health, drainage.

This wonderful plant you paid big bucks to own was raised in potting soil (believe me, no commercial grower would ever use garden soil in pots, they are in the business of growing, producing healthy plants...think about that) and given just enough water, just enough air and continuous chemicals that are prescribed just for this plant. It looks beautiful, the picture of health and you pay good money, take it home away from everything this plant needs and knows, stick it in a pot with a shovel full of who knows what. Obviously this plant will not do well. You feel bad, you feel it is your fault and you go buy another and try giving this new plant a home hoping it will thrive. Hopefully, you will give up with trying to reinvent something the commercial gardeners have already discovered. Just get a bag of cheap sterilized potting soil for this next plant. Trust me, plants are tough and adaptable but putting a plant in a pot with less than a gallon or two of soil and expect that plant to continue looking healthy is setting yourself up for failure...why not give that plant the best chance of survival?

You don't think I've tried making my own soil? I've been around and watched others trying to make their own potting soil. They buy the vermiculite, the peat moss, the decomposed organic matter, perhaps some mycorrhizae and bacteria to add after BAKING the whole mess in an oven (PU). Test for chemistry and pH! Pebbles and rocks are not helpful at all for drainage. Been through enough testing of soils as well as Soils 101 to know this is a fact.

Then there is the perched water table. If one puts rocks, gravel at the bottom beneath the soil (any soil) in a pot, people think erroneously these large pieces of rock help with drainage. Large pore spaces below tiny pore spaces create a perched water table. When the plant and soil are watered, all the tiny pore spaces of the soil have to be filled (saturated) before the water is then able to move into the large pore spaces on the way down to the drainage hole. Causes soggy soil, root rot and generally all the symptoms of over watering.

Order the dang potting soil over the internet! If commercial plant growers who are very concerned about every cent, use commercial potting soil why would anyone else want to try making their own soil? To save money or even better produce a science experiment where you have to purchase all the ingredients and sterilize. Very little soil is actually involved. Definitely more work, more money and too large of a risk.