The pleasure of growing and harvesting your own veg and growing your own flowers cost-effectively are probably the primary reasons why you’re growing plants from seed. But you’re also eager to do things naturally. You’d love to harvest veggies that are pesticide-free, and you worry about the potential impact of pesticides on your family’s safety and on nature.
So, what can you do about the multitude of pests that seem to have been waiting for spring to arrive? We look at some of the ways you can keep those creepy crawlies at bay.
One of the ways to keep nasties out is to grow your plants under netting. However, it has its pros and cons.
On the plus side, you’ll keep most of the big pests out – but unless you choose a very fine netting, tiny ones, like spider mites, will still find their way in.
On the downside, you will exclude pollinators along with pests, and you may have to intervene by shaking the plants to let pollen spread or even using a small paintbrush to hand-pollinate crops.
Your choice of plant varieties will also have an impact, especially on disease resistance. Open-pollinated plants are usually pretty tough, and certain hybrids have been bred to withstand common plant diseases.
2. Use a Natural Repellent / Insecticide Spray
We love this recipe for making your own dual-purpose insect repellent and insecticide. Yes, it actually kills certain pests on contact without being poisonous. But if you apply it once weekly, it will also keep a lot of the baddies away. Here’s how to make it:
Use 10 to 12 cloves of fresh garlic combined with 4 to 6 really hot peppers or 3 teaspoons of chilli powder. Add two cups of water and a tablespoon of dishwashing liquid. Combine them all in a blender and leave to stand. Although some people say the concentrate is ready within 24 hours, we prefer to let the mixture steep for 48 hours.
Next, strain the mixture through a cloth or a coffee filter. Voila! You now have a concentrate that you can keep in a glass or plastic jar for several months if need be. You’ll use about two tablespoons of concentrate per 1 litre of water.
As with any pest control method, this one has pros and cons. It will kill most soft-bodies insects with ease, and it deters most moths from laying eggs on plants they would generally consider to be good food plants for their larvae, but it’s extremely variable.
You will need to experiment a little and test the mixture on small areas, waiting a day or two to make sure it doesn’t burn the plants before spraying entire batches. Sometimes, the chilli is too hot, and hot sunshine on delicate seedlings sprayed with this mixture is almost certain to burn them to death.
I used this mixture in commercial horticulture and on quite a large scale, and we were always careful to spray late in the day and test each batch of concentrate. We were also able to limit the variability of the mixture a little by using chilli powder instead of fresh chillies.
We found our chilli and garlic spray to be effective on aphids and other soft-bodied sap suckers, and it reduced populations of red spider mite quite nicely, but once the plants were already infested, we found that spraying every second day for a week or so seemed best. It also seemed to be distasteful to beetles – but not to thrips. Try it yourself to see what works for you.
As a footnote, plain soapy water will control a lot of pests, including aphids and spider mites, without any additions – but do remember the potential for burning and experiment with caution. Half a teaspoon of most brands of dishwashing soap per litre of water should do the trick. For a safer bet, you can also buy commercial insecticidal soaps.
3. Collars Against Cutworm
I don’t think anyone really likes using cutworm bait. The granules lie around getting mouldy and you can’t help remembering that they are poisonous – even though it’s a very mild poison. But if your seedlings are getting chomped off at ground level, there doesn’t seem to be much else to do – or is there?
Cutworm collars provide the answer. If you have a lot of problems with cutworms, start your seedlings in trays or pots – then use an empty toilet-roll pushed a little way into the soil to protect the tender stems when you plant your seedlings out. You can also use disposable drinking cups to do the job. Problem solved.Your plant will be protected until they are too big to make a tasty meal for a cutworm.
4. Give Slugs and Snails Beer and BBQ
To control slugs and snails, look no further than two things most Aussies love: beer and BBQ. Wood ash is great for keeping slugs and snails away from plants. The slimy guys won’t cross a strip of wood ash. Don’t use ash from BBQ briquettes, however, and be sure that the wood ash doesn’t touch the stems of your plants.
Beer traps are a popular way to kill slugs and snails. They’re attracted to the smell of the yeast and you’ll make the trap hard to escape from once they’re in. Just remember that these traps do attract snails and slugs, and they’ll attract them from quite far away, so site them a distance away from your tender seedlings.
Use a 500ml plastic bottle with holes big enough to allow a snail to enter cut near the top of the bottle. Add a little beer (it doesn’t have to be fresh – dregs will do) and partially bury it in the soil leaving the top sticking out.
If you needed one more reason to grow basil, lavender, and other aromatic herbs, this could be the one. Most insects don’t like strong aromas, so borrowing the smell of your aromatic herbs to apply to other edibles makes great sense.
Collect trimmings from your aromatic plants and leave them to steep in a bucket of water in the sun for a few days. Once strained, the result is a fragrant brew that most insects will avoid. Just strain it well before spraying or it will clog the nozzle of your spray bottle.
A few drops of soap adds to the potency of the mixture and helps it to spread and stick to the plants’ leaves. As always, test your spray on a small area just to be sure it won’t harm your plants.
What About Store-Bought Concoctions?
Home gardeners don’t have access to the most toxic products on the market, and that’s a plus from a safety perspective. Nevertheless, if you use commercial pesticides, be sure to read the label carefully and observe all the recommended safety precautions.
If a pesticide isn’t registered for use on edibles, don’t use it. If it is, observe the safe harvest period given on the product packaging or the leaflet that comes with it. Concentrates have more potential for harm than mixtures, so be sure to keep them out of reach of children, wear gloves when handling concentrates and mixes, and avoid inhaling spray mist.
Aside from the lower-toxicity insecticides, there are also completely non-toxic options – just remember that “organic” and “non-toxic” aren’t necessarily the same things. Nature has its share of poisonous compounds!
Our opinion? Use what works provided you can do so safely. We like the idea of non-toxic products or home concoctions, and they should help most folks who don’t want to buy expensive products and who don’t have very heavy pest problems. If that doesn’t work, a bottle of concentrate should last a few seasons. Choose the most environment-friendly options you can find.