I like machine sewing but I'm really not a big fan of stitching on net fabrics since they are a little tricky to sew. However, I wanted a large insect mesh curtain for the entrance door of my polytunnel to help prevent insects such as wasps, bees and any large flies from coming in. We get a lot of birds in the garden, including pigeons who will readily eat greens, so I was hoping to discourage them from coming in too.

There are occasions when you may want to give wildlife access to your greenhouse or polytunnel and whatever is growing inside. There are also times when you may want to prevent access and particularly if you are looking for extra protection against flying insects that can cause a lot of damage to your crops. Fine mesh netting will help you to better control what can get into your growing area while you keep the entrance open for necessary ventilation. See how to create a large curtain panel and can use these same techniques to also make more coverings for windows and openings.

1: Choosing Netting Fabric

You need to choose a netting size large enough to cover the area that you are wanting to curtain off. I bought some fine mesh insect netting which can restrict and prevent carrot fly from damaging crops. The type of netting that you select may depend on what you are looking to keep out of your growing area. I wanted a fine mesh to deter small insects and bees, wasps and flies from coming in. You need to look for specific insect netting which is for outdoor use since ordinary fabric may not last long outside.

Measure the whole of the area that you want curtained off with net fabric. Once you've got your measurements, add 1 - 2 inches around every side to allow for sewing hems. Hemming the fabric, if it requires it, will help to prevent the edges from fraying. You can also hem with elastic tape inside on the top section to hang your completed panel up.

Consider whether you want to have a larger amount of excess fabric on the sides of your panel so that, in the case of a greenhouse door or entrance, you can also secure your netting to the sides of the polytunnel or greenhouse. Open sides on a curtain that just hangs straight down and moves with the wind will allow crafty bugs and insects to simply fly in.

2: Pinning Raw Edges Ready to Sew

Netting is not the easiest thing to sew but if you leave the edges raw on this fine mesh, they're just going to fray right up and be ruined in no time at all. I'd rather put in a little work and have this last longer. Since this is very fine, I found the easiest way to hem the edges was to fold up the raw edge by approx ¹/_⁴ to ¹/₂ an inch and then fold it over again so the raw edging is neatly tucked away in the seam. Then pin this to secure it all in place.

You can pin to secure this double folded hem or you can iron the fold to help keep it in place while you sew. Pins can drop out easily from this type of fabric and this is a good reason why you may prefer to iron it instead. I pinned both the sides and the bottom of the fabric but the top edge of the material was stiff and did not need any hemming.

If you iron the hem, please note that you should never iron on the fabric directly because it can melt and ruin the fabric as well as your iron. So you need to use a piece of material such as cotton fabric over the top to act as a barrier. For ironing, you need a dry iron with the steam function turned off and set it to a medium heat. 

3: Sewing Machine Settings

You can use a standard foot on your machine for hemming. A zigzag stitch is better than a straight one. It will take longer to sew but will give you a much stronger hem that will secure those raw edges in place better.

I used a 1.2 stitch length and a number 5 stitch width on my Brother machine. I also swapped out my standard needle for a Sharp 60/8 which is better for fine fabrics. This was a brand new needle and I had no issues with it while sewing. Just slowly stitch along that double folded hem you made.

How to Sew a Double Folded Hem

4: Zigzag Stitch

You can see my zigzag stitch here. This would not win any neatness awards if you were making these net curtains for your home but it does make a very strong and secure hem for your greenhouse or polytunnel curtain panel.

5: Securing the Fabric Panel

Once you've done your sides and bottom to stop the edges fraying, it's time to focus on the top of this curtain panel. You need to think about how you will secure this panel to the inside of your structure. For me, it was having a length of elastic tape across the top which could be tied at either side of the polytunnel entrance.

You may want to make your own ties at the top so you can knot them around a pole or the frame at the entrance. Think about what the best option of securing this panel is for your specific situation.

6: Making an Elastic Hem

I measured a long piece of elastic tape which was larger than the width of the panel. I left an excess of tape on either side for tying it to the side frame of the polytunnel. I placed this tape about an inch down from the top edge of my netting panel and then folded the edge of netting down over the top of the elastic and pinned.

I used the same zigzag stitch settings to sew all the way along the top, just underneath the elastic tape, being careful to not actually stitch through the elastic. This made a hem with elastic tape secured inside all the way across. I kept a pin in to keep the tape in place on the left and right corners ready for hanging.

7: Sewing Elasticated Tabs

An optional extra I added to my panel was to stitch elastic tabs down both sides. I made about 3 tabs on each side. This was so I could also secure my curtain panel to create fewer gaps where insects can fly in. If you just let the curtain hang down, the wind will blow the panel and create areas where bugs can fly straight into your greenhouse or polytunnel. So having some method of securing at the sides is also useful.

If you are sewing on elastic or tie tabs, you probably need to switch your machine needle out from the 60/8 sharps one to a needle suited to heavier fabrics and material. I switched to a universal 80 size.

Netting Provides Ventilation While Reducing Insects

The photo above shows how I used the elastic to tie the insect netting panel to the frame of my polytunnel. It is held in place at the top and the sides. On one side, I secured the elastic tabs with some velcro which gives me easy access to get in and out. Now I can keep the door open and rolled up to let in air and ventilation in on a hot day and deter insects from getting inside. 

Image Credit: all images on this page belong to the author of this article, Marie Williams Johnstone