Creating another grow season w/greenhouse

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movenosound
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Creating another grow season w/greenhouse

Post by movenosound »

Has anyone tried giving potted bamboo a second growing season by controlling it's environment in a greenhouse? The purpose would be to give the plant another few months to put on more root mass, more rhizome, and more culms, though I would expect that any rhizome or culm growth would be minimal, not the serious culm growth that we all look for, but the purpose here being to help a potted plant along towards a healthy mass above and below ground that will help to speed it's development once it is in ground and to make sure that once it is placed in ground that it will be able to survive more than a less-developed plant from the same size pot.

My thinking is that when a division is taken, and then potted, which I have noticed is a standard practice, as opposed to putting a division directly into the ground, the newly-potted division is allowed to stabilize and develop in-pot, sometimes for a few years, before being planted in ground sold, depending on the propagator's intention. My personal experience has shown me that this can have a huge difference on a plant's development. Last year, of five Atrovaginata that I planted in-ground, two were well-developed in five or seven gallon pots, which they had been in for over a year ( last year was their third growing season since they were divided including the season that happened right after they were taken), and three were divisions taken the year before, sold in two gallon pots. The two more developed plants were dramatic in their differences in development, producing a spread of over twelve to thirteen feet, and this year more than doubling culm number and diameter. Meanwhile, the smaller, less mature divisions have shown little development, and one has even looked as though it may give up the ghost, though it was one of the very last to go into the ground last year, and not looked after as much as the others.

Clearly, the reasons that the two did so much better than the other three are obvious. My motivation in trying to create another short growing season in the winter is simply trying to speed along a division to healthier size and state to give it added vigor in a smaller amount of time.

I assume that bamboo require a dormant period in order to properly continue growing, so what I propose is allowing a potted bamboo to experience temps and conditions of fall for a month, and then moving them indoors to slowly reverse this, until they are back into 'spring' like conditions, and warming them and increasing light until three months before the expected natural growing season here (around march here), and bringing them back down to dormancy quickly, then placing them back outdoors to allow them to continue with the normal season.

I know that this may end up causing the normal growing season to be less productive, as the late fall and late winter are still probably vital periods of food storage for the big push of shooting season. If the above idea turns out to be too much of a violation of the plant's normal operation, then maybe this controlled environment could be used to extend to rhizome growth and root establishment period in the fall, and give a bit of a jump on the culm establishment period in the spring?
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Re: Creating another grow season w/greenhouse

Post by stevelau1911 »

What I've found by using a greenhouse is that within the 2 extra months of growing season, my bamboos tend to put out a lot of new shoots since it really allows the shoots that started coming up in September to fully establish, so trying to give them a zone 9 environment helps young plants establish. I think the rhizomes run for a bit longer too since my heteroclada seedlings are now all popping rhizomes out of the drainage holes and making lots of whip shoots likely due to the extended growing season. If you have a greenhouse, I think it would be ideal to help get new plants more established especially if your growing season is as short as mine.

The mosos that I over-wintered indoors started out slow as many of those didn't shoot until late May, but they seem to be the first ones to generate rhizomes which probably showed that they matured more over that time frame than the ones outside.

The one thing I did not see about extending the growing season is any substantial upsize compared to the ones without the treatment since upsize deals with other factors such as heat and how well developed shoot buds are as well as the size of the existing culms.
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Re: Creating another grow season w/greenhouse

Post by movenosound »

Good to know Steve!

I didn't expect to gain any size as far as next season's culms, though I do want to avoid preventing an upsize in culm height and diameter by screwing with the dormancy period.

Have you had any experience, or read anyone who has seen a specific dormancy time as being required or necessary? For instance, is a period of a month in the 40-50 degree range going to be sufficient enough dormancy to allow a plant to be moved into a new cycle? Guess what I am looking for on that topic is a minimum required time, and possibly minimum temperature to initiate dormancy and to end it.

I want to reiterate to anyone reading that this is not an attempt to find a way to force bamboo into a bigger size faster. What I am hoping to achieve is the creation of much more established divisions in terms of root and rhizome mass, so that they might set up quicker and begin to spread over a larger area after being planted in-ground. I guess that a hardier root and rhizome mass would contribute to larger and more culms come shooting time, but I have patience enough for that, I am more concerned with covering ground and creating potted bamboo that can be given, sold, or traded to someone with more confidence that it will survive and establish well for them.
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Re: Creating another grow season w/greenhouse

Post by needmore »

Moveon - please keep in mind that when Stevelau talks about his heteroclada & moso he is talking about seedlings, not divisions and they behave differently from divisions.

My growing season is roughly late March through late October. We get frost in late October and ups & downs in temps for several weeks. Real cold can start as early as early December and last until early to mid-March. I overwinter most of my pots in a double plastic hoop house, I turn on the heat when it gets below +20F at night. There is frequent frost in the hoop house but the soil in the pots never freezes, it is also very very moist in there all winter. Some days there will be leaf growth if we have extended warm/sun but essentially dormancy all that time.

On a few occasions I have brought small plants into my sun room where they get all day sun, bottom warmth from a radiant heated slab and it never gets below +70F in there. My goal was to try and push the season to let small plants have more growing time - I would not let any single plant spend more than one winter this way. The results were disappointing and unless it is a very rare plant that I want to keep an eye on all winter, I will not do this again. MY original parvifolia spent winter #1 this way and I ended up planting it out in late Feb as it looked so unhappy. It did produce a new culm but I think it would have been better off not doing that. In any case I almost lost the species and I had gone to great lengths to obtain it so planting it out in Feb was an act of desperation. It quickly recovered that spring.

I have tried it with others as well and none were as unhappy but I do not think it helped them really. Not so much the lack of dormancy but I think the indoor conditions are tough to keep bamboo happy and it is very easy to screw up the watering with a small plant.

When I tried this I left the plant outdoors through several frosts until the first cold night that would have frozen the soil in the pot - they came in that night.

Any new culms produced indoors have been weak and floppy, plus took forever to harden off. The plants of the same species that wintered over in the hoop house instead, despite the slower start, grew WAY past these indoor guys in the spring so they clearly were much happier in the other conditions.

Your mileage may vary...
Brad Salmon, zone 12B Kea'au, HI
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movenosound
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Re: Creating another grow season w/greenhouse

Post by movenosound »

Thanks needmore. I've always thought that there must be something, some fine line between the indoor environment and the outdoor that keeps us from growing things indoors. I tend to think that it has something to do with the air, the humdity, the constant movement that the outdoors usually experiences, and the deprivation of CO2, but I have no real idea, just a hunch. I guess what I would try, if anything, is something more like a glorified cold-frame environment. But, at that point I might be just as well just putting up some of the protective measures folks have mentioned for boos overwintering their first year or in zones lower than they are rated.

This might seem out there, but did any of your indoor environments have supplemental lighting? I was thinking of allowing a significant amount of airflow from outside through the greenhouse, and supplementing the evening and morning light, (especially since its dark so late and so early up here) by using an HID light, probably a 800 watt metal halide to start, and maybe accompanied by another 800 watt HPS, to see if spectrum matters, and hope that the warmth of the light will be enough to keep them from danger or dormancy, and that the addition of outside air will keep em robust.

I think I will start this little experiment with Bissetii divisions, since that boo seems intent on giving me so damn many!

BTW, you have your own private Parvifolia import? Have you discussed it at length in another thread? I have picked a couple up from Bamboo Gardens outside Portland OR and am really looking forward to seeing what they do. Do you think that your Parv is very different from the lineage that produced the Garden's?
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Re: Creating another grow season w/greenhouse

Post by needmore »

My parvifolia came from someone that imported it(I did not), my guess is that Bamboo Garden got theirs from the same person.

I did not provide any supplemental light, where these were indoors there is enough natural light to have had hot peppers, bananas, and papaya all flower and set fruit indoors so it should be plenty for bamboo.
Brad Salmon, zone 12B Kea'au, HI
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