I thought it might be enlightening to see what I typically use for my propagation work. If you have any tips or suggestions, let me know.
Most of the grow area has been emptied out into the yard. But there are a few prized propagations that I’m still hesitant about – the very large Abutilon varieties in particular. While those stay inside, the lights have to be on. So what do you do? Turn it into a seedling start area!
I have several grow trays, and three wood box planters with various vegetables started as well, but the indoor environment with heat mat significantly speeds up germination time.
This is a somewhat structured analysis of my propagation efforts. I originally wrote this a few months back, but thought I’d share.
Fast-growing softwood herbs in water (and even potting mix or perlite/sand) are pretty much guaranteed. Using a bubbler to aerate the water helps, but with or without, it typically works. Mint, basil, sage and less often, but still very frequently, Rosemary work very well.
Greenwood from many vigorous bushes roots in high quantities (table below).
Hardwood cuttings in water don’t seem to work. They just get old and slimy and rot. I have tried with and without alcohol in the water. It seems the alcohol staves off pathogens for a short period but eventually it still withers. I imagine this is because the alcohol eventually breaks down and the water is no longer sterilized — all of which happens WAY before a hardwood would be ready. I have not found any recommendation or reference to growing hardwood in any literature – only long-term bundles in dirt, usually over an entire winter.
Times of year vs. type of cutting
As of now, 09-12-2017, my knowledge is that hardwood cuttings take about a year to root, and are typically done in the winter, with little work (e.g. cut and bury, and forget for a year). This is good for experiments but hard for planning (e.g. for the garden or to sell).
Phytohormones and propagating/growing
Cytokinins are the hormones for cell differentiation, and are responsible for rooting. In nature, they are regulated with auxins that promote shoot growth to balance the two out.
- Auxins are found primarily in top shoots, promoting “apical dominance”
- Adding rooting hormones promotes somatic embryogenesis on a callus site
- As such, the questions are:
- can we force even more root initiation by reducing free flowing auxin?
- Does leaving a leaf or leaves on increase auxin and thus decrease rooting, even though the intention is usually to provide carbohydrate energy for roots?
- A 40/40/20 sand/perlite/peat moss gets dry too easily and is harder to push the cuttings down (dibber helps but the higher sand content doesn’t keep the hole shape well
- 30/60/10 or 20/70/10 sand/perlite mix works really well.
- Going to try 20/80 or 30/70 sand/perlite, think it will work even better.
- Sand has great drainage except it is variable and can get extremely hard if dried out, or extremely mushy if too wet.
- FINE Pine bark and potting soil is going to be my new potting medium for non sterile requirements. Great nutrients and superior drainage given the pine bark, and potting soil blend with fertilizer is cheap enough that mixing is no longer useful to me.
- Heavy perlite mix seems to cause algae growth where it turns green. Overwatering is obviously the primary issue but perlite seems to promote the growth. Need to check.
Medium pot size and transplanting
Starting propagations and seedlings in cell trays is pretty cumbersome, especially propagating, because the stem length already makes it untenable for really small grow trays.
In the future I think it would be better to use standard pot sizes that fit inside the grow domes evenly, but would allow the cutting to grow uninterrupted to a pretty large size before needing a transplant.
This also makes sense with the heating mat under grow trays propagation method, which I think is going to produce much better results.
SH vs. SW vs. HW – Problems
False positives are common across all species, but seem prevalent in hardwood. I attribute this to the excess energy available in a woody stem. These also take much much longer to show any signs, presumably because they don’t have the same vascular structure as green/softwood, nor the same levels of hormones like auxin, but this is just speculation. Either way they take longer and are prone to false positives.
Conversely, there are often false negatives with adventitous rooters, where the root structure is highly developed, but there are little to no leaves. Transparent planters are useful in this regard, but unless they are standard squares, they are not worth the trouble.
It has become apparent that transplanting to check root growth is vital as many plants may not rot but look healthy for weeks.
Only for softwood/semi-hardwood
For me, two weeks is the absolute maximum, with 7-10 days being optimal. If there are no signs of even protoroots at any nodal primordium, then toss it out. I have found that the likelihood of rot and disease spread is much greater than a missed opportunity.
With hardening off
I moved the cuttings indoors and bumped the temperature up, and setup more lighting for them. I also took the bag off a few. They started turning brown and curling up VERY quickly – like one day. I had to put the bag back on and return them to lower light area. We’ll see what happens.
The cuttings likely need to be off to the side, and the seeds front and center.
I’ve been able to successfully propagate a pretty diverse set of species, but there are some bottlenecks with the overall process:
- Finding space when repotting
- Keeping plants watered appropriately
- Some are too wet, others dry with ebb and flow system being uneven and sputtering pressure
- Not everything is part of the ebb and flow and still has to be hand watered
- Misting plants is still manual because of nozzle precision and directional control
- Oxygenated water trays is really just a reaction to a bad setup
- Keeping gnats under control or removing them entirely
- Algae growth in soil and perlite
- Massive heat drop at night (might not be an issue) from ~74 to ~58 except for trays with heat mats and domes
- Bottom heating to stimulate growth
This list is not exhaustive. I’m sure there are plenty that I missed, or did not have time to add! Also, these are not formal percentages, but rather estimates:
Legend: SW = softwood, HW = hardwood, SH = semi-hardwood, GW = greenwood
|Plant||Cut type||Medium||Notes||Success rate||Time of year|
|Regular sage||SW||Soil, water||70-80%||Whenever|
|Euonymus||SH, SW||Sand/perlite||Surprisingly successful||95-100%+||Whenever, tried in late summer/fall|
|Japanese maple||SH||Sand/perlite||Surprisingly successful||50-60%||Whenever, tried in late summer/fall|
|Strawberry||SW||Sand/perlite||Not 100% confident yet but looking good overally||80-90%+||Whenever, tried in late summer/fall|
|Geranium||SW||Water, Sand/perlite||Mixed results. Have gotten fast growing new plants off plain water then soil. Bubbler + water has not been as good as expected.||50%+||Whenever, tried in late summer/fall|
|Peppers||SW||Water, Sand/perlite||Pretty decent, not as good as basil/mint. Need further study, not as much experience to inform the percentage.||80%+||Whenever, tried in late summer/fall|
|Rosemary||SW/SH||Water, Sand/perlite||Perplexing, this has not been very successful. SW seems the only way. HW rots/molds almost every time.||60%||Whenever, tried in late summer/fall|
|Tomato||SW||Sand/Perlite||Surprisingly ineffective. Droops sadly almost immediately. Maybe technique?||0%||Whenever, tried in late summer/fall|
Getting them to root.after initial growth has much lower success rate
|80%+||Whenever, tried in late summer/fall|
|Spirea||SH||Sand/Perlite||Surprisingly effective!||90%+||Whenever, tried in late summer/fall|
|Russian sage||SH||Sand/perlite||Pretty easy. Need to be very.slowly hardened off though||90%+||Whenever, done in fall|
|Variegated flowering maple||SW||Sand/perlite||Surprisingly effective||95%||Whenever, done in fall|
|Forsythia||SW/SH, LEAF||Sand/perlite||Insanely effective||95-100%||Whenever, done in fall|
|Climbing hydrangea||SW||Sand/perlite||Green shoots are adventitious rooting, hardwood does NOT work at all. Possibly trichomatic||80-90%||Whenever, done in fall|
|Rose of Sharon||SW||Sand/perlite||Only got one shoot, but it was great||100% (only did 1)||Whenever, done in fall|
|Pineapple sage||SW||Sand/perlite||Easy, adventitious roots, trichomes||95-100%||Whenever, done in late summer/fall|
|Boxwood||SH||Sand/perlite||Surprisingly effective, small sample size||100%||Whenever, done in fall|
|Sedum||SW||Water||Surprisingly effective and very vigorous root growth, small (1) sample size||100%||Whenever, done in fall|
|Rhododendron||SW/SH/HW||Sand/perlite||several false positives due to excess carbohydrates triggering bud growth||0%||Whenever, done throughout summer, fall, late fall|
|Nandia domestica||SH/SW||Sand/perlite||No growth, the nodes have “snapping points” that seem to naturally fall apart||0%||Done in late fall|
|Lamb’s ears||SW||Soil, sand/perlite||Seems pretty easy||80-90%||Done in summer, fall|
|Fatsia Japonica||GW||Potting mix||Large fat stems make it hard to get properly buried. They seemed pretty mildew resistant.||30-40%||Done in late fall|
Over the last two years, my understanding of and relationship to soil has changed in some very useful ways.
I am writing this post to share as I think most people’s understanding of traditional landscaping and yard care is severely flawed.
That might seem like a quite a claim, but let me just try and back up and explain myself.
If you go to the store and look in the gardening section, what do you see? Moss out! Pesticide, fungicide, synthetic fertilizer, grass seed with five different types of patented technology. The acrid smell of concentrated chemicals. Then you have what seems like a newly emerging section, targeted to the opposite side – mycorrizhea, organic this, organic that, b supplement, root stimulator, even really fancy stuff like bio char… the list goes on.
Now, I’m all for the latter half. And I use copper fungicide, and neem oil for extreme cases. But I get the feeling that the average home owner who has a yard is basically looking for a one size fits all cookie cutter solution.
Newhome-owners – whose home was likely created by the nuke and pave approach – cut everything down, destroying the habitats, scrape the topsoil off to get to hard pack for the foundation, and then slap sod and nursery plants on top after building, and water, water, water.
Then you have existing home owners, who more often than not try to emulate this ideal by forcefully trying to circumvent nature by dousing, spraying, tearing up and reseeding and replanting.
Now, I’m not gonna pretend like I’m not doing what I just described. In fact, I spent considerable blood, sweat, tears, and money trying to get the yard in order. Nature had taken over and I was trying to push back the tide of time.
And I’m not against this. I really like manicured yards, contemporary gardens, English gardens, Japanese gardens, they all have amazing aesthetics. They all go against nature in some ways. They attempt to control it.
My only complaint is that the approach to typical gardening seems to constantly work against nature, rather than trying to understand and manipulate that understanding for personal interests, in a more symbiotic way.
When I first moved in, I was very excited about composting. I built up a compost bin from some leftover concrete blocks (using mortar mix) and I felt like I was going to recycle all these household food scraps, grass clippings and branches in my own little revolution to reduce, reuse, and renew.
The problem is, compost kind of sucks.
I spent more time than I probably should have researching ways to accelerate composting, from using compost teas to home built digesters, to crank powered grinders to increase the surface area for acceleration.
But after I learned about some interesting precepts in permaculture, I really started to question the overly complex approach. After all, nature handles things pretty well and it isn’t building large digester systems – or is it?
At some point, I got really tuned in to mycorrizhea and their benefits to roots. Pouring over YouTube videos about these fascinating fungi, I ordered some on eBay.
I did some preliminary testing indoors with my propagation efforts, and it really seemed to have made a pronounced volume of roots. I also found they were nearly immune to root rot.
Fast forward to having a giant cottonwood tree cut down, and a pile of wood chips in the yard. After a day them sitting, I was reminded of my compost, which reached 90-120 degrees in the center.
However, these heat piles are not very useful for traditional gardening. The anaerobic nature deprives of any beneficial organisms, and the heat would kill the roots of a plant, so that’s not very useful.
However, when I spread the mulch out for winter, months later I found a thick white mat of mycorrizhea under all of it.
After that, I was convinced this approach was right path and I decided to eventually dismantle the compost bin. Now, I simply dig up holes and bury compost – food scraps, all of it. The way I see it, putting the nutrients directly in the ground is like a free, all natural, time release fertilizer.
Now, I’ve taken it a step further. Falling branches get snapped into twigs and tossed in as mulch. I even reuse cardboard – I dig around the plant and use it as a myco feeding, biodegradable weed barrier. My recycle bin is a lot lighter too.
Who knew Amazon Prime could be supplementing my garden needs like that?
I’ve now become obsessed with what I can put into the yard. I keep getting free wood chips when I can, so I can constantly keep things mulched and cover the ugly stuff.
And if it’s summer time, I burn the big stuff that falls. I even burn my kiln dried lumber scraps from wood projects. These are safe and untreated.
With this, I help amend the carbon. And if I want, I can douse it with water and make bio char without spending a ludicrous amount of money.
This new perception has all benefits and no drawbacks.
I never have to wait for compost to amend the soil.
I never have to host a giant pile of dirt.
Cardboard is reused
Weeds are diminished.
Having bonfires means permanently amending the soil.
I highly recommend you consider these tips for you garden.
It’s easy and fun to focus on the success stories of propagation, but it’s not terribly useful for broadening your understanding.
I decided I would spend some time reviewing the myriad failures I experienced.
This is not a specific timeframe, but given that I started documenting the process at a length comparable to a growing season, I’ll just consider it a “a year in review”.
Types of failures
There’s so many ways to fail, but for me they fall into only four broad categories.
You would not expect it, given the sterile environment which I tried to maintain, the premixed and seemingly innocuous potting soil I used, but I have found my grow area harboring the following:
- Fungal gnats
It was quite a surprise to find an earthworm in a pot that contained only potting soil from the store, but there it is. While I don’t consider spiders and worms pests (quite the opposite), I just had to mention it.
However, before I refined my watering regimen, I dealt with a plethora of gnats. I tried diatamaceous earth (worthless) reduction in water (doesn’t kill the larvae), repotting (helps) but ultimately I only had success after a combination of these and more importantly, fly paper. I had not expected such success, but I was happy to see them go.
Unfortunately, the aphids took up the slack with great vigor, and while they are basically relegated to the confines of the closet, it’s still disconcerting to have these pests in the house.
Neem oil has been mostly useless, and I don’t like to use it indoors anyway. The safest and most effective solution I’ve found has been horticultural oil, which is both a pesticide and fungicide, and is diluted manually. Plants seem unfazed by my vigorous dousing. Though, I think I’d focus on beneficial predators if I was doing anything I really planned on eating.
While this is open ended, I am really talking specifically about fungal disease. The one that has definitely caused several deaths (including a 2’5 foot tall Forsythia, proving size is irrelevant) has been root rot. Other times it’s the nearly equivalent “damping off” – again, both fungal. My guess is that the culprit was either fusarium or pythium.
These most always seem self inflicted as a result of over watering. They are also associated with poor drainage, but I use a very friable combination of fine pine bark and potting soil. The problem is that potting soil is incredibly well engineered to retain moisture, more than one might actually desire. I’ve basically switched to watering once a week for most, some of the dry loving plants (rosemary, lavender, sage, etc) two weeks. Though, you can use the vigor of the plant and the expected growth, alongside the soil moisture level as a guide. For example, I have wormwood that is supposed to hate being overly wet, yet constantly wilts because the growth is staggering. It towers over many plants and thus I have to water it quite a lot. Conversely, plants that do fine in normal watering arrangements when suffering root rot, will be stagnant and wet. This is usually reason enough to uproot them and inspect.
Fungal disease to the roots manifests itself in a signature withering and browning of the mass. If the roots are not bright white, almost clear, then they are probably on the verge of a full fungal attack. By then end of it, the roots will no longer be plump. Instead they will only be wiry and thin. The outer mass of the root had necrotized and only the thin inner structure exists. Unlike pests, fungal disease is pretty much beyond repair. It is important to quarantine or dispose of these plants as soon as possible.
If caught early, you can repot the plant in freeway fresh dry soil, and apply a fungicide. Clip off any brown roots which are useless anyway. It’s good to clip off the equivalent quantity of leaf mass as well, since the plant no longer has the capacity to handle its vascular responsibilities.
Hormones and physiology
This is probably the biggest thing I and imagine those starting out, overlook. Hormones aren’t directly within our control (well, not very much anyway), and the way they form and aggregate depends on many factors, but the ones I’ve learned to be most common are time of year, species, and type of cutting. Hardwood naturally does not root even in the same season, let alone time frame, so these should be considered a unique type in my opinion. They callus and form root cells, but it takes much longer.
Beyond that, there are softwood, Greenwood, and semi ripe hardwood, ordered by freshness, and consequently vigor, and more importantly, hormone concentration and distribution. I’ll not get into the details, but do read “reference manual of woody propagation” and “American horticulture society plant propagation” if you want the extreme detail. Both of these are seminal works and cover probably all you will ever desire to know.
Regardless, ensuring the species you are propagating will actually work for the type and time of cutting will save you lots of frustration. For example, climbing hydrangea leaf cuttings will NOT ever form into a full plant. The leaf will grow roots, and then just sit there. The same is true for Forsythia. I’ve grown rather impressive roots on single leaf, but no stem ever grew, because it lacked the node that contains the type of cells that differentiate into leaves and stems.
Each plant or sometimes family is unique. The season, area, number of nodes, synthetic hormone type, hormone concentration, rooting medium, and many other factors are all unique.
This boils down to three factors: nutrients, light type and intensity, and water. These are probably the easiest to control for and growing plants in a standard potting soil with time release fertilizer (adjust/amend as needed), a high output white grow light, relative humidity of 50-60%, and plant/family specific watering schedule has provided me all I needed to grow everything from baobob to nepenthes, to all sorts of herbs, vegetables, flowers, and trees.
It’s starting to get warm enough outside that I’ve decided to experiment with a few of the diminutive propagations. These are low priority or interest items that I’m less concerned about losing. Granted, the nights are still a few degrees away from freezing, and many of these are used to growing in a 65-70 degree environment, so there is some risk associated. However they’ve got a good layer of mulch which tends to heat up as a result of decomposing. The attendant processes, including formation of thick mycorrizhea mats (myco love wood chips), the vast layer of nutrients, worms, and pure rainwater will certainly weigh heavily on the success of these.
Some inherently do better, especially those with firmer stems. I had rather large pumpkin starts that became wilted and shriveled from the cold – others decimated by slugs. However, some that appear to be damaged by a bit of frost tend to spring back after a few days. I had wanted to build a nearing frame but hadn’t gotten around to it. For now I’m keeping the heat mostly off inside the office to keep the ambient temperature down.
I’m anxious to get these out primarily so I can make more room for vegetable starts!
Some daffodils I got from the Seattle garden show. 1 day under red/blue spectrum and they all bloomed at once.
Recently planted bare root fruit trees. Plum, and 5-cherry (5 grafted types). I repurposed my vegetable planter as it was too deep, but is prefect for keeping fruit trees in check, and it looks kind of distinguished. When spring comes and the yard is cleaned up, it’ll look a lot nicer.
Back to the grow area. Here’s a wide angle shot of the action.
The sheer number of wormwood plants has forced me to move most of them out of the closet and into the bedroom. They’re doing fine here though. The purple tint provides an interesting aesthetic.
Pumpkin seeds overflowing out of the pot, looking for some soil to drape themselves on…
Various exotic seeds I planted are not fairing that well – but their germination rates are supposedly months, not weeks. My two sequioadendron giganteum sprouts died of root rot it appears. I am hoping some others will sprout.
Forsythia so long it cannot support itself – it just drapes over all the others like a crowd-surfer at a concert.
A demonstration of how incredibly long these Forsythia cuttings have grown.
The sea of wormwood continues unabated…
Rutabaga “crops”. Looking a little splotchy but overall doing good. They are a lot fatter than this picture would lead you to believe.
Probably the coolest development so far. My baobob tree has germinated! The seed is incredibly tough and has slowly been cracking open for weeks. I tried to manually dislodge it but nearly pulled the seedling out, so I left well enough alone. Of all the exotic seeds I bought, I was really surprised this was the second thing to actually germinate. And it came up pretty quick, too.
Japanese Lilac’s are starting to grow more shoots and develop some decent size. They are a couple inches tall at this point. I’ll move them outdoors once this PNW mini-freeze is done and there have been signs of a solid spring start.
Smattering of different things. Lilacs, Peppers, Wormwood, Lambs ears, and seedlings (chinese redbud, baobob, kochia scoparia, rose hips).
Fatsia Japonica cuttings from my neighbor. Any leaf that does not have the very clear cut off edges is all new growth. These have already developed a pretty intense root system.
My pepper cutting, rooted for months and producing pepper. There are about 4 peppers on it, albeit small.
Garlic bulbs my wife threw out – now towering past the light I put them under.
Butterfly bush (Buddleia) growing several new shoots.
Euonymous keep on truckin’; slow, but steady. They are typically medium growth shrubs, but in here they are a bit slow. However they have a very high success rate (95%+) and are pretty root rot resistant.
Wormwood in front, but behind that are several rooted strawberry stolons (“runners”) that have actually flowered and are starting to form fruits. At this point my indoor edibles list has inadvertently grown by leaps and bounds: peppers, strawberries, rutabaga, garlic… (to say nothing of various herbs).
Squash seedlings. My wife made squash for dinner, and later on handed me a plate of washed seeds, preempting my instinctual urge to save anything that looks like a seed. Now that’s love. I tossed them in a pot and they are already quite large
My original variegated abutilon cutting. It is nearly the same size as the parent I cut it from, since its had all winter to grow!
This Abutilon towers ominously. I’d say it’s 3-3.5 feet. I continue to prune back a mess of leaves just to keep it in check. I’m hoping it will really take off outside. Most all of these plants will inevitably serve as mother stock for future cuttings. Once they are of a size where pruning is actually necessary to keep them from sprawl, I’ll expect my game will level up quite a bit. I know for certain that I have outgrown the bounds of this closet. I have yet to figure out a permanent solution for rotating stock out, beyond a heated greenhouse, which is out of the question for now.
Russian sage in front – slow but steady. One leans on a pitcher plant for support. They get a bit leggy in here.
The other side of the wormwood forest. I have been giving some away at this point. The amount of trimmings I have taken off of all these would be a sizable little brush pile.
Different kinds of mints, basil.
Hope you enjoyed – happy almost spring!