Which insects are you planning to guard against?
Everything!
CWB and anything else that might do damage.
Also pidgeons, etc. And muntjac deer, rabbits, foxes all of which are regular vistors.
If you plan to open one end for pollination of some plants at certain points of the year, there is a high risk that the insects will simply fly in at that point.
The idea is not to leave it open, but rather pull it back over the first two hoops to close off the rest for the (short?) pollination period.
Not fully thought through because it just dawned on me that the runners and courgettes aren't the only crops that need pollination...more thought needed.
It is more common to protect a class of plants, which all need the same growing and/or pollinating conditions, rather than aim to permanently protect a wide range of plants that will clash in requirements.
I looked at making a series of small cages around each of the double rows, but it uses :
- 3x more pipe
- 2x more netting,
- uses up all the access spaces unless you make the sides vertical
- has to moved every year for rotation
- has to be lifted up for weeding or harvesting (giving access to the bugs)
This just seems easier, cheaper and pretty permenant.