On my balcony, I used to put a new portion of fresh soil next year after the harvest (honestly, if not even replacing all the amount). Why? Because the soil in pots on a balcony looked poor, loose and deteriorated after a winter season.
You see, the soil is not only a dark matter from where the roots grow – it is also a living place for lots of symbiotic (friendly) microorganisms, worms. During spring-summer-early autumn time plants protect the soil from drying and loosing its biota (living organisms). If not to carry about it in winter – no surprise to have poor result later!
This year I decided to be wiser and save on soil by two simple ways. These methods allow the soil to stay fresh and dark black, and even enrich it with additional nutrients:
Method #1 – cover
Put dry leaves on the top of the soil and cover with another (empty) pot upside down so that there would be an air space. Leave some places uncovered.
I also put the (soft) shells of young walnuts under the leaves. Look around and use any kind of plant matter: dry leaves, stems from harvested plants, etc.
Any dead insect could go there too, because it is also an organic matter. I would only doubt about birds’ features, but should be good too.
Method #2 – grow
Growing one-year decorative plants. Some decorative plants bloom only one season and stay colorful till late autumn. Good way to decorate the balcony and at the same time to prevent soil from conditions of a winter season.
In agriculture, this method is known as “second crop”. “Second crop” is a crop planted after harvesting another crop on the same land earlier in the season.
While in agriculture second crop is usually another kind of grains, on a balcony one may use a “second crop” for a decorative purposes, why not?:)
You may be interested about soft walnut shells. Here they are on a picture. Walnuts on a tree have a soft green turning to dark brown/black hulls. This green hulls turn to dark brown/black because it is known as a great natural source of iodine.
In folk medicine, spirit tinctures could be prepared using black hulls of walnuts. I am not deep in this topic yet, that is why no recipes here:)
However, you may like to read my another post about walnut tree which grows just right to my balcony: Walnut tree grows here / Prophylactic self-isolation series. Day 257th.