Maintaining Soil Life in Containers - is it practical, or do we need to feed container plants?

[headfullofbees]

NOTE: Whilst I personally am using no-dig approach to gardening, this question in relation to container gardening is specific to all methods that rely on 'feeding the soil' rather than 'fertiizing the plants'. So it also applies to chop and drop, green manure etc. Does 'feed the soil' work in a container where it's so easy for conditions to develop that kill off the soil life?

In my garden beds I use a no dig approach where you feed the soil life and in turn, IT feeds the plants. It works very well and it's easy. A 1 inch topping of garden compost once a year and the beds will grow as many crops as you can throw at them all season.

But I have very large patio areas where I need to use containers. Realistically, can you keep the soil life alive in a container? If you let it dry out briefly you'll kill off soil life. Too much heat, too much cold, too much water etc. Also, we keep hearing how important trees, shrubs etc and their root systems are to the soil life and thus to our plants - something that our container soil won't have access to.

How relevant is mycorrhizal network to veg growing (I know bacteria is more important to veg). But if it has any benefit at all to veg/annuals the moment you use a container you aren't going to fair as well as in garden beds

I get good results from my containers but I feed them all summer long with compost tea, worm tea, comfrey tea. I tend not to trust that the soil life will survive long enough in a container for me to treat it as I would a garden bed. I tend to empty out all but the biggest of pots and put in fresh potting soil each year.

Gardening in beds is a easy. You plant it and for the most part do nothing else until harvest time. But containers are hard work.

Or am I wrong in thinking that 'feeding the soil life' can't work just as well in containers?

Containers, unless they are huge have the problem of drying out, which means more watering & drainage to sluice out nutrients, & having them nutrient rich tends to discourage mycorrhizal networks.

 

[skinyea]

So contrary to what you said intitially you're not relying on the green manure you grow in your container. You're bringing in leaves and peas from elsewhere.

I'm bringing in whole lawns full of clover, peas, beans, grass, comfry, nettles, weeds, leaves, kitchen scraps, cow and horse manure etc - in the form of garden compost. Roots of anything grown (in some beds up to 4 crops in a year) is left to rot down. But it's not enough in a container *in my environment*. It works brilliantly in beds and even very large containers.....but not in patio containers. Likely for a combination of the reasons already explained.

i can get 2 - perhaps 3 years out of a patio container for flowers and less hungry crops (although fresh potting soil and fertilzier gets bettter results), but for squash I get best results replenishing each year with plenty of compost and manure and in addition feeding with compost teas etc throughout the growing season.

In my polytunnel raised bed (12 ft x 3ft x 2f high) I'm now on year 4 growing potatoes, then tomatoes, cucumbers and peppers then covering with an inch of compost for the winter. Potatoes go in Feb, Tomatoes (already fairly large in pots) go in May when the potatoes come out. Tomatoes come out about November and then a layer of compost goes down until the following Feb. I tend to add another thin layer of compost from the hotbin in feb - simply because I put the hotbin in the polytunnel for winter and it's easy to just dump it on the beds when I move it back out in spring. Worm farm also goes in and that leaches some nutrients over winter. There isn't enough light to grow through the winter here so best you can do is keep something dormant in the ground until spring - which isn't going to take nutrients out of the soil. I've done that once, but I only have the bed empty for 3 months so I find it's more bother than it's worth. The layer of compost protects the soil. The big polytunnel bed was initially filled with garden soil, logs, twigs, leaves, manure, compot etc.

This is getting weird.

 

[Meadowlark]

This is getting weird.

LOL, it's past weird.

 

[Susan BBPM]

Containers, unless they are huge have the problem of drying out, which means more watering & drainage to sluice out nutrients, & having them nutrient rich tends to discourage mycorrhizal networks.

Hadn't considered the flushing out of nutrients due to constant watering. Good point.

Also hadn't considered how valueable (or not) mycorrhizal networks are when confined to a container.

 

[roadrunner]

I'm just considering one possibility here - mycorrhizal network.

"The word mycorrhizal relates to "myco" (fungi) and "rhiza" (root). It refers to the symbiotic relationships that fungi have with plant roots, aiding absorption of nutrients and helping them grow. Mycorrhizal fungi pass water and nutrients to the plant, and the plant in turn supplies the fungi with some of the food that it generates by photosynthesis – the process by which plants use sunlight to transform water and carbon dioxide into oxygen and energy.

Because the fungi are far more extensive than the plants’ roots alone, they efficiently ‘mine’ the soil for nutrients and water, and the food from the plant boosts the fungi growth."

Complete Guide to Mycorrhizal Fungi | BBC Gardeners World Magazine

What is mycorrhizal fungi and how does it work? Find out in our complete guide, from BBC Gardeners' World Magazine.

www.gardenersworld.com

According to the Gardeners World article that I've quoted the above from, 90% of plants make use of mycorrizal network. (Brassicas don't).

Containers don't have access to this network, so assuming it's working for you in your beds (and if you dig your beds it may not be) then you'll be at a disadvantage when you use containers - they won't have access to it.

However, if you make up for that deficit by feeding the plants with organic fertilizers you make up for it.

It's one possible explanation. But I've tried bottomless containers and it really doesn't help much.

I think it depends on what type of mycorrhizal fungus. I would think there are many types of fungi that can get into pots via its spores landing in the pot. And then you got the large pots that sit on the ground and have drain holes where the fungi can gain access, in addition to arriving via its spore.