Organic Insecticides

OK. I give up. That title isn’t really the best. It’s slightly misleading because the purpose of organic gardening is to build a healthy eco system. That means that the idea of an insecticide just won’t wash as there are many bugs and other critters in your garden that are beneficial to you and your plants. However there are some nasties out there. And getting rid of those without killing all the good ones can be a challenge.

So perhaps I should have called this hub “Keeping the pest insects and other black hat fauna down while allowing the good guys to flourish and maintaining a healthy balance in your garden”. Or perhaps not.

The first thing about controlling pests organically is that you need to have a different mindset. I have read gardening books and websites that talk about sterilising your soil and eradicating everything that might eat some of your crops. If you choose to work organically you will not be able to do this. There will always be some pest insects in your garden. But that’s ok. They need to be there to ensure that the good guys have something to eat. And you need the good guys there because there will be times when the population of the others grows and something has to get rid of them.

Planting

The first step in controlling pests comes in the winter when you are planning your garden for next year. You need to think about which plants you are going to grow to keep your garden healthy. The plants that you can choose fall into two categories. Those that attract beneficial insects, and those that repel the pests.

Anything that has blue flowers will attract bees and wasps. I know most of us have grown up with the idea that wasps are bad. I’m not suggesting that you put up with a whole nest of them in your garden but a few visitors can be helpful. Most kinds of wasp are predatory and the things that they eat will eat your crops. Other colour flowers are useful too. I grow calendula and marigolds around my veggie plot. Their orange flowers attract the bees almost as well as the lavender and they have the added benefit of repelling slugs and snails. So plant colourful flowers near your vegetables. Who said your veggie plot has to be ugly?

There are also catch crops that you can grow near your precious crops. If you plant something that the bugs like more than your veggies they might be persuaded to go there. In my small garden I don’t really have space for this but I know some people who have success with it.

Garlic is probably the king of the repellent plants. I grow it around the outside of the vegetable garden and in amongst the roses. Aphids hate it, and the cabbage white butterfly will usually give it a wide berth. Slugs and snails are supposed to be allergic to it, but to be honest I haven’t really noticed that. Snail trails on the garlic leaves in my patch area give a bit of a clue to their allergy strengths. Carrot fly will also avoid garlic. Of course the big plus for garlic is that you also get a crop from it. And home-grown garlic beats the store bought stuff by miles for flavour.

There is a third kind of plant that you can choose. The ones that are resistant to infestation in themselves. Use heritage plants and save the seed from the strongest plants in your garden. After a couple of generations you should have plants that are ideally suited to your micro-climate. Or you could just plant acres of chard (silver beet) nothing seems to eat that.

Mulching has many benefits. It keeps the weeds down. It adds organic material to the soil. It conserves water. And some mulches will keep away the pests.

Pine needles are great fertiliser for strawberries and slugs and snails hate walking on it. I know of some gardeners who cover the paths between their plots with pine needles. It seems to stop the snails sprinting from one patch to another.

Eggshells are similar to pine needles in that slugs and snails don’t like putting their soft bodies over the sharp edges. There are also some bugs that will avoid the speckled white of crushed eggshell on the ground as they seem to think that their kind has already laid eggs there and so they go somewhere else.

Coffee grounds are very high in nitrogen and so are very good for your leafy plants. They also make excellent fertiliser for citrus. Worms love coffee and will come from all over to munch out on it. And best of all it is toxic to slugs and snails.

Sprays

There are three sprays that I use regularly. They are all homemade and free.

Garlic. Put a whole clove of garlic into a pot of hot water and leave it overnight or longer. Put the liquid into a sprayer and spray over your plants. Most bugs will now give your plants a wide berth.

Milk. When you get to the bottom of a milk bottle and there is just a little milk left but not quite enough to use don’t throw it out. Mix with about five times the volume of water and spray over your plants that are infested with aphids. The aphids will drop right off.

To improve both the above sprays you can mix a little washing up detergent with the spray. This will improve its sticking power so that it stays on the plants for longer. But mostly these liquids are not considered organic but it’s up to you.

The third spray I discovered by accident. Grab some seaweed from the beach after a big storm and soak it in a bucket of water for about a week. Pour off the water and dilute to about the colour of weak tea. Use it as spray on the leaves of your plants. I did this originally as way giving the plants some fertiliser but have noticed that sprayed plants seem to get much less infestation that unsprayed ones.

Hard work

Keep your garden areas tidy and remove possible living spaces for pests. Old bits of wood are ideal for many bugs to live under. Clear them up and don’t give them somewhere to hide.

Get out in your garden and look for the bugs. Crush them or put them in salt water. Wear gloves if you are squeamish. Then add their remains to the compost pile. They have taken something from your garden. It’s only fair that they put it back.