Temperature underneath a tarp vs outside temperature

[stevelau1911]

After tying culms down and laying tarps over them, I stuck 1 weather station sensor in one of the tarps to get an idea of what kind of temperatures the plant actually experiences under there. After 10 days, outdoor temperatures have varied from 20F up to 56F, spending most of the time in the 30s according to the outdoor sensor. The sensor inside the tarp has only varied from 43F to 51F during the same time, and the temperature under the tarp was almost always higher than the outside temperature. Aside from reducing the temperature variation, there seems to be something that's keeping the area under the tarp warmer. There are leaf bags and the tarps allow some light penetration, but at this rate, it will be very hard to get below freezing especially when the snow provides further insulation.

For example right now it is 46.8F vs the 38.5F outside, and that differential is at about the minimal for the day since it is at the warmest part of the day. If it never drops below freezing under a tarp, then it may be possible to keep large tropical clumpers under tarps to grow them permanently in colder climates, but it's way to early to say it won't get below freezing because we really haven't had a cold spell yet. Soil temperatures are 46F(tarp) vs 39.5F (outside).

If the soil around the bamboo never freezes, that may also mean that root growth may never stop completely over the winter, or may buy the shoot buds extra time to develop resulting in more & larger shoots in the spring, but this is the first year tarping large bamboos so I'll have to wait another 4 months to find out if the tarps make a difference.

[marcat]

Organic material under the tarp create the heat. I do not think you will be able to bend large tropical clumpers under a tarp to protect them. They just to strong. You would need a 100 X 100 M tarp for just one. And it would be one big ugly mountain stick ing up in your yard. Trying to protect my B. vulgaris Wammin with minimum succsess using tarp like stuff. Next year I am going to make a ridgid stucture with wood covered by green house plastic all bolted together. with a Wammin being so short (16ft) this might work.
MarCat

[stevelau1911]

http://www.ebay.com/itm/3-Mil-Clear-Gre ... 5d2571a07d

It seems like a giant tarp will cost at least a couple hundred bucks if it is ordered online, but this is the best one I can find which is supposed to be strong along with good light transmission. 48ftX100ft for 245$, + free shipping is usually a better deal than the plastic tarps the sell in the local gardening stores. It might be feasible to tarp a 20ft phyllostachys since they can be tied down with tent spikes very easily, especially when the soil is wet after a good rain, but I can see why it may sound impossible to bring down a large tropical clumper for winter protection. I have never grown tropical clumpers to a large size so I have no idea how hard it is to protect them, but if there is a feasible cost effective way, I would like to know about it.


After having a few inches of snow on the ground, the temperature differential has jumped to near 30F as it is around 15.7F outside vs 44.6F under the tarp. It looks like having snow on the ground will further protect the tarp area from dropping to extremes, especially when there are leaf bags there in order to catch the snow drifts from blowing snow.

[dependable]

On years I have left over potted stock, I tip them over and tarp them for the winter. It helps them look good and start growing in the spring. The main reason is to protect the leaves from dessication. If the plants are well established in the ground, they have a lot better time keeping their leaves hydrated. It takes a lot out of a potted boo to refoliate. This winter, around here, it has not been necessary yet.