I first heard about Grow Cover from Warm Earth magazine and am interested in using the product to protect our veggie beds.
We live at 500m in southern Tasmania so I have some questions regarding load and wind bearing properties of the fabric. I would ideally like to create walk-in structures.
We are thinking of a frame made of steel reo rods or star pickets with heavy gague irrigation pipe for the arches with timber frames at either end.
Your frame sound good and very similar to ones other customers have built and are very happy with, particularly those made with star pickets and heavy duty 50mm poly pipe.
The frames do need to be well secured to the ground and the poly pipe braced so it doesn't bend back and forward. This can be done with timber battens etc.
The fabric can then be stretched over the frame and firmly secured. When tightly stretched it sheds hail and deflects wind better. It also discourages, though it doesn't stop, snow from accumulating.
HD Grow Cover is described as heavier and thicker, does this mean it has more wind resistance than the lighter fabric?
Yes, it will have slightly more wind resistance, but for a walk in tunnel the GrowCover HD would be a better solution because it stretches less giving a firmer more secure cover.
This means snow and hail will tend to slide off rather than pool on the fabric.
We noticed in a heavy hail storm that the hail just rolled off.
We can experience winds of up to 90k regularly and there is the possibilty of light to moderate snow at any time. We also have some extremely heave frosts.
I would prefer to use the lighter fabric if it would cut down on the wind resistance of the structure, but could it cope with the load of snow or ice from frost sprinklers?
We have had winds of this speed and found our walk in tunnel cover in GrowCover HD withstood it fine, (even though our frame is far from perfect) the important thing is making sure the frame and fabric is firmly anchored to the ground.
Because the fabric is permeable to air the pressure differential on each side of the fabric is lessened making it more able to sustain strong winds. A key element is securing the fabric at ground level. This makes a great deal of difference.
Lighter fabric on low hoop houses was also fine as long as it is firmly attached. We have not used this on walk in tunnels and have no customers who have so we have no experience of how it would be.
Is the HD fabric better at protecting plants from frost?
It is the same for both. Incidentally, we wonder whether you would need to use frost sprinklers in your tunnel structure. We don't know from personal experience because GrowCover gives good protection with the level of frost we get here.
Do you know of anyone using a dome design to improve aerodynamics?
Sorry but no, but would love to know. From our own experience we know that our garden hoop houses pictured on our web site have never collapsed or been damaged by strong winds. We are near the south coast and we occasionally get storms with winds of 100k plus.
Would the fabric survive the effects of poultry if the gardens were used as chicken tractors or would the structure required additional wire mesh?
The GrowCover HD would be tougher and therefore better for a chicken tractor, and as long as secured well should not require additional wire. GrowCover is very strong and even if accidentally cut will not run.
I don't know if you have any problems with possums or other animals but customers who have bought GrowCover with this specifically in mind have found it stopped them getting through.
Wire may catch on the fabric and cause unnecessary wearing.
Do you have any information on the effects of the fabric on increasing or maintaining soil temperature?
We do not have any scientific data on warming and maintaining soil temperature but from experience it does. Our customers confirm this too.
With weather extremes (37 c max last week, 14 c today) and a shortened growing season, we can immediately see the benefits of crop coverings.
We have found that in protects plants in hot weather. Yesterday we had 38 degrees and the young cucumber seedlings in our walk in tunnel were just fine at the end of the day.
We think this is because it maintains a level of moisture inside the structure and lessens the drying from hot winds.
We would expect it to also lengthen your growing season, enabling you to sow earlier in spring and harvest later into autumn.
We are restricted by cost, however, so any information you can forward to us will be of great assistance.
If you are contemplating more than one walk-in tunnel we would suggest that you get enough fabric for one structure first.
When you have built and used that for a bit you will much better understand the best way of designing your structures which you can than utilise for your additional ones.
What we suggest is that you tell us what the dimensions of your proposed structure(s) (total length of support hoop, length,width and height of tunnel) and from our experience we can suggest the most economical way of cladding it.
We have done this for lots of customers. If your sizes are a bit flexible we can then suggest the best width of fabric to use which will reduce any wastage.