When most people think about nurseries and plant propagation, they conjure up rows and rows of black pots and the smell of moist palettes of artificial fertilizer. But there is no natural law which dictates this to be the only, or even a preferable way in which to propagate plants.
While in-situ propagation from seed has been proven to be the healthiest and most energy efficient means of mass propagating most plants, sometimes you need to create sheltered controlled conditions for certain plants to get established.
If you are in a situation where plant pots are not available, if you cannot direct seed your plants, or you want to avoid the pots altogether, there are several other methods to get plants established.
Here I share a few ideas about natural, simple nursery establishment and protocols.
Nursery beds: moving away from pots
What is a pot? A containment for soil. In moving away from pots we look toward how to create a functional containment so we can control the conditions of germination and growth. For most purposes, creating single-reach (~2ft wide) and double-reach (~4ft wide) raised beds serve the purpose of propagation well.
Even in the most remote of places, there are many things you probably have on hand which you can used to create adequate nursery beds, such as:
- Parallel windrows of compacted subsoil, or a pit
- Large rocks
- Woven plant material
- A hole in the ground
- Straw bales for lining beds
- Hollowed out bales for planting within
- Dimensional lumber or sawmill slabs
Each of these materials have their own qualities and life expectancy, but all of them do a fine job of retaining soil. If you only need a seedbed for a few years, then using organic materials like logs, wood and bales makes good economic sense, since it will inevitably decompose into humus which is beneficial for the site in the long term.
Organic material also holds moisture and insulates soils, and so can help buffer soil moisture and temperatures.
If using logs to line your beds, think toward doing the extra planning to cut and cure and inoculate the logs. This will add another yield to the nursery system, and may inoculate the soil with these species.
Making the bed several feet deep and adding a large quantity of decaying biomass to the bottom can help retain moisture, promote good drainage, maintain soil activity, and give the plants extra depth to root into without requiring additional rooting soil.
A layer of rotting wood mixed with subsoil and topped with several inches of straw or animal bedding is a layering pattern which I have found suitable. The rooting soil mix goes on top of the straw/bedding. The straw acts as a filter and helps to keep the rooting soil from falling into the lower layers.
Adding a subsurface irrigation pipe (perforated drain-pipe, or 1-2” pvc with small diameter hole drills at regular intervals) can be of a lot of benefit. Plants grow their roots towards water. Superficial watering means superficial root structures. Getting the water into the depth of soil means the plants have deeper root systems. This is particularly important for trees, but just as beneficial for perennial herbs and understory plants.
Working on contour, and/or creating level areas for the beds to sit will also go a long way toward water retention and ease of access/maintenance. Good design pays for itself in no time.
Using other growing spaces as nurseries.
If there is already an established growing system, it is often simple enough to designate a space within it for propagating plants to expand into other systems. These plants can also provide a wide range of other benefits to the system.
An annual garden bed doing double duty as a clover nursery at my home. Cole crops and
winter squash planted into a living mulch of dutch white clover (Trifolium repens). The
clover suppresses weeds, is chop-and-drop mulch, provides nitrogen fertility, supports
pollinator activity through the whole growing season, and has a reasonably
non-competitive root system.
The clover is also very cold hardy and is allowed to overgrow the cole crops in the fall, and winter. In the late winter and early spring, the clover “sod” is chipped out to give the transplants a wide birth to get established. The sod is then transplanted where it is desired in other perennial growing systems — such as along footpaths and under young trees and shrubs where it forms an expanding ring of soil cover as they expand.
Comfrey and Sage growing as perennial shade, windbreak, pollinator support and
chop-and-drop mulch elements in the same garden as shown above.
The comfrey and sage are prolific in the garden context where water and nutrients are not limiting factors. The plants are regularly propagated by division and transplanted out into other systems.
A similar tactic can be employed by a wide range of plants grown for division propagation, suckers and seed.
Soil rooting medium – ideas and recipes
Finished rooting soil made on site
As is a typical permaculture orientation, it’s important to develop a knack for using whatever materials you have on hand to achieve a desired goal. Here are some great soil ingredients which are pretty easy to come by no matter where you are.
Charcoal – the primary ingredient in most mixes I make nowadays. If you are cooking with wood, you generally always have charcoal on hand. And if not, it is very easy to make in large quantities, and is a very light weight, nutrient retentive medium.
I have gone up to 50% crushed and sifted charcoal in rooting mixes to good effect. Charcoal is very nutrient retentive, but if it is not “primed” with nutrients before entering the soil mix, it can suck up lot of available chelated nutrients, making them less available to young plants who need them immediately.
One simple way to prime charcoal is to crush and sift it into a watertight container and inundate it with liquefied nutrients such as urine and compost/manure tea for a day or two. Remember to keep it aerated by vigorous stirring so it does not become a source of less-beneficial anaerobic microbes in your soil mix.
Leaf mold and native top-soil are a great addition to the rooting medium
Leaf mold is rich in humus, and contains many soil active organisms which can inoculate your rooting medium and ultimately your whole system. In most situations it is a direct replacement for peat and moss.
You can make “leaf traps” in or around you nursery to help capture leaf material close to the site you want to use it. A leaf trap is just a pile of branches laid on the ground. Leaves get trapped up in the sticks and accumulate where ever you want. Simple and effective.
A side note: many take issue with harvesting leaf mold believing it is robbing the system of valuable resources. No doubt it is an extractive practice which needs to be understood as such. However, when working within a self-contained system, re-distributing moderate quantities of one wild-born resource in order to establish productive elements in the same system which will increase the initial resource over their lifetime seems to me perfectly justifiable. A practice of taking small quantities from a variety of locations helps mitigate the impact on any given area, as well as diversifying the mix.
If you have done your research, you can collect leaf-mold and topsoil from the rhizosphere of native or established plants which host the same mychorrizal and bacterial associates as the plants you are propagating. For instance, transplanting rootlets and soil from a nodulated black locust for your locust seed bed.
While I am not an expert on mycorrhiza, I am convinced from experience that collecting soil from beneath established plants of the same species, genus or at least family for use in propagating is worth the effort. For example, soil from a native Choke Cherry (Prunus virginiana) when propagating root cuttings of common domesticated plum (P. Domestica) varieties. This tactics stands good likelihood of getting beneficial mycorrhiza into the root zone of plants right off the bat.
Compost — for obvious reasons, compost is an important ingredient in rooting soils. The concentration of easily accessible chelated nutrients, and active biological processes make it easy for young plants to find what they need. Plus, you can make compost pretty much anywhere, with anything you have around.
Native worm castings. Photo courtesy of UC
Davis Integrated Pest Management Program
Compost worm castings are also highly beneficial ingredients. Compost worms are also typical component of most permaculture establishments. And if you do not already have worms, you probably should, and they are very simple to get established. Vermicompost has the added benefit over compost, in that it ought to contain viable worm eggs, which will be transplanted all over your system along with the plants.
Beyond compost worms, you can find castings from other insects as well. Native earthworm castings are typical in many regions. Other insects may also be semi-domesticatable, produce nutrient-dense biologically-active castings, and may more easily eat what you have around, such as black soldier fly larva which make use of putrefying materials like animal carcasses, and termites, which eat lignin-rich plant tissue.
A side note: I almost always have mesh/screen material on hand when working on projects, since they are so useful. In making rooting medium I make sure everything is sifted through at least a .25 inch (6mm) mesh. You can also make screens by loosely weaving withes of coppiced willows and the like into baskets or winnowing type trays.
Other things you can add if you have them
Sand – helps to maintain drainage and can be used to add bulk to your other ingredients. You may be near a stream or beach where sand is readily accessibly. Sharp “construction” type sand is helpful, but all sand has similar properties. You can add quite a lot of sand to a mix without much deleterious effect other than a dilution of nutrients.
Sifted subsoil — depending on the nature of the subsoil, it may be beneficial to incorporate some into the mix, or to an under-layment of organic material in a nursery bed to help add bulk, fill in gaps and increase moisture and nutrient retention.
Bone char is the byproduct of the destructive distillation of bones in the absence of oxygen. The volatile organic material burns/melts off (creating another valuable material called traditionally “Dippel’s Oil” or commonly “Bone Sauce”, leaving the mineral structure.
Bone char can be crushed and sifted like charcoal but has the added benefit of chelated minerals of tricalcium phosphate and calcium carbonate. It too should be primed with nutrients.
Making the most of your nursery
As is the typical permaculture orientation, you can think of your nursery areas in terms of layers, communities and functional interconnectivity.
For instance, you can seed hard to establish understory support species with your seedling trees and shrubs. When you go to transplant your trees out, you will also take with you strong populations of plants that otherwise would have been difficult to propagate in situ.
You can also grow edible and medicinal plants in your nursery beds to provide a productive living mulch. For instance, seeding shade-tolerant salads with your tree seedlings, or alliums in between rows of shorter herbaceous plants.
If you are concerned about insect herbivory, think toward pest confusing inter-plants, or trap crops.
If concerns about soil pests like root-grazing nematodes in long-standing nursery soils exist, think toward establishing a rotating cover crop system with species such such as marigold (Tagetes patula), sunn hemp (Crotalaria juncea), rapeseed (Brassica rapa), and radish (Raphanus sativus).
You can position crop species in a bed to maximize each plant’s preferred sunlight conditions — mimicking the layers of a woodland edge. Taller species in back, working toward shorter ones with shade tolerant plants behind and underneath.
If you are trying to root cuttings or promote root growth in general, you can utilize the excess rooting hormones produced by Salicaceae family plants such as willow and poplar by inserting live-stake cuttings side-by-side with your other cuttings.
These cuttings will begin taking root and will exude the hormones into the root zone of the other cuttings. The willows can be cut back as the other cuttings take off.
If your nursery space has tree cover, you can think toward thinning and limbing trees or making use of patchy sunlight to give areas of the nursery more or less sunlight during different times of day or seasons.
When rooting plants from cuttings it is important that you keep the leaf-temperature lower than the ambient air temperature to minimize loss of moisture due to evaporation. Giving cuttings natural dappled light throughout the day, as especially in the afternoon, is a simple way to accomplish this.
Sizing you beds so that they can easily take a row cover or cloche is smart if you desire to get your seedlings going earlier in spring for transplanting the same year.