If you’re a regular reader you’ll know that we’re trying our hands at growing some vegetables. Our home-grown vegetable patch includes beetroot, silverbeet, lettuce, coriander and rosemary. Welcome additions to the herb collection that we already had—birdseye, habanero and Apache chief chillies, bay, basil, mint, flat-leaf parsley, tarragon, sage, lemon thyme, thyme, oregano and garlic chives.
With the continual rain we’ve been having lately (so over it!), there’s been an explosion in our little vegetable patch. The vegetables have shot up and we’ve been very happily harvesting the leaves for salads and cooking. But this rapid growth of our plants has brought a new challenge—aphids. No doubt attracted by all the tender new leaves, aphids have had a population explosion within our little garden. They’re even on the habanero chillies! These nasty little sap-suckers destroy new growth so we’ve declared biological warfare…
We’re trying to be organic and given that these plants are for us to eat—not the aphids, as they seem to think—we’ve had to read up on how to get rid of the aphids without using harsh chemicals.
Method 1: Companion planting
Coriander is supposed to repel aphids. Aside from wanting to use it in our cooking, its aphid-repellent properties were part of the reason we chose to grow it alongside the others. Our four planter boxes had quite deliberately been stocked with a mix of the beetroot, silverbeet, lettuce and coriander, rather than having each pot with only one type of plant in it.
Three of the four pots included coriander and the aphid assault started in the pot without coriander. So it’s fair to say that there may be some merit to coriander repelling aphids, however they have spread to the other pots and now are even on the new coriander leaves…annoying little critters.
Method 2: Lady beetles
I don’t know about your area but it’s not often we see lady beetles in gardens around here these days. And lady beetles are the natural predators of aphids. But with no flowers on the balcony, and no more space and pots to plant with flowers that would attract them, it seemed this option was not available to us.
Method 3: Soap spray
The organic gardening community swears by using soap spray to control aphids. So we gave it a go…
Mix together 1 droplet of environmentally-friendly dishwashing liquid, 1 tsp vegetable oil and 1 cup water and spray on the plants affected by aphids.
It does work but the process needs to be repeated every few days on an ongoing basis to ensure that you wipe out all stages of the aphid population. Unfortunately, part way through this process I noticed too late some lady beetle larvae on the chilli bushes, but the soap spray also gets rid of them.
Not sure how the lady beetle larvae turned up in our little garden and definitely wanting to encourage them, soap spray was no longer an option. We decided to leave spraying anything for a week and keep an eye on the plants for the appearance of more lady beetle larvae.
Method 4: Garlic spray
More reading uncovered the suggestion of using a garlic-infused water spray to control aphids. All the while wondering how this might affect lady beetles, we decided to try it.
Finely grate 1 or 2 cloves of garlic into a cup of water. Allow to infuse for 30 minutes or so. Strain into a spray bottle and then spray the affected plants.
So far so good. We’ve used this application three times and the aphids don’t like it. The lady beetle larvae that have reappeared seem undeterred, contentedly munching on aphids. Maybe we shouldn’t be surprised. Most dishes taste better with a hint of garlic, don’t they?!
What we’re really keen to find out is how the lady beetles know to appear. How do they know when a particular spot has an infestation of aphids? Their arrival seemed so random but they turned up right when we needed them. And while they haven’t obliterated the enemy yet, we know they’re not far off it.