It’s just dirt, right?
Well yes, and no. You see plants need many things that “just dirt” may not be able to provide. Growing seeds have different requirements than mature plants. Different mature plants even have different needs. It can be confusing, I know. Let me see if I can shed a bit of light on the subject.
What dirt is best for starting seeds?
I find that when dealing with a problem, starting at the beginning is often the best. So, in the case of growing plants, starting from seed is about as close to the beginning as one can get. Of course there is the which came first, the chicken or the egg scenario, but let us leave the circle of life quandary behind us for now and start with seed growing. If one ponders nature and the wonders there of it seems like growing plants from seed should be a no brainer, right? Well, wrong. And why is that you may ask? It is simple and has more to do with humans than it does with nature as we have this nasty habit of messing things up. Food plants have been manipulated by humans since we figured out what we could eat that didn’t make us sick. So we collected the seeds that made bigger, tastier and faster producing plants. It is only logical really. But this selection led to other variations that make those let the seeds grow where they fall notions of nature become slightly more complicated. Now we are required to treat these precious little germ bundles with tender care. So back to dirt. For seedlings you want fresh sterile soil. Please don’t get lazy and just whatever was in that pot from last season. That “old” dirt may have fungus, pests or even diseases that the previous inhabitant grew resistant to. It also has many nutrients that seedlings not only crave but need depleted from last season’s crop. There are many seed starting mixes available and those are great for those of you who don’t want to get too dirty (ha ha, I’m so punny) but for those of you who wish a more hands on approach (look! I’m doing it again!) you can create your own mix. Your end aim is a mix that is fine and uniform with great aeration and free of pests, disease and weeds. So, one third pasteurized soil or compost, one third sand, vermiculite or perlite and one third peat moss should do the trick. We used compost, peat and vermiculite in our mix. It was a little on the chunky side so next season we will make sure to create a more fine texture.
What is the best potting soil or raised bed soil?
Surprisingly enough this answer is very similar to the seeding mix with one difference: texture. At this stage in a plant’s life we are no longer so worried about their delicate nature and more concerned with production and the long haul. With that in mind, large chunks of compost, peat and vermiculite and aid with extend release of nutrients and moisture. These chunks will break down with time and lend their goodness to the mature plants. A little warning here for clarification. When it comes to compost you don’t want large moist or “green” chunks as those will rot, create heat and draw attention to unwanted pests or disease. Large “brown” compost pieces such as dried leaves, bark and the like will be fine. Look for my compost article for more detail on the different types of compost ingredients.
After the season is done, what do I do with all this “old dirt?”
Ah ha! I am thinking ahead for you. Don’t you fret! Old dirt is fine to dump into your compost pile, if you do that sort of thing. The heat from the maturing compost and all the microbes in there will eat away any nasties that might be hiding in the old dirt as well as refresh it and put all those good nutrients back in. We have a tumbling style compost bin as well as a larger compost pile. Also keep in mind the joy of crop rotation. Some plants, such as beans actually add nitrogen to the soil, so these make for a great crop for “fixing” old dirt. To reap the benefits, simply till the plants under and as they decompose the nitrogen will be released into the the soil. It’s science people! But here is an article if you want to know all the juicy details:
If you have ridiculously deep raised beds as we do, then there is a neat little trick that might make your old dirt, not so old. It’s called Hugelkultur. This is where one uses old wood that rots with time to make a raised bed. Another article, BAM!:
https://www.permaculture.co.uk/articles/many-benefits-hugelkultur So, the dirt on the top might be old, but the dirt on the bottom is still “working” and thus nutrient rich. All might be needed is some deep tilling and some added compost, peat and vermiculite and it back to business as usual.
Check out our video to see me getting dirty. (OK, I’ll stop with the jokes for now) https://www.youtube.com/watch?v=71Bf5LwJIZU