There's more photo's but I don't know how to share them.
TL;DR: windy balcony up high invaded by aphids, what to do?
Situation
I have a balcony some 10 storeys high, in the Netherlands, and like to make it into a lush miniature balcony garden, so I have a lot of plants.
Unfortunately the balcony often gets a lot of wind, and nearly all the plants are being invaded by aphids of various sorts. Many of the plants are dying or struggling, with a small exception of the broccoli, hedera helix, some gifted alium bulbs, and a recently added hop plant which grows like there's no tomorrow.
The balcony only has an open front; the sides and top are all closed. Despite that, even the plants in the back are regularly shaken by gusts of wind.
What I've tried
- given the plants plenty of water and nutrients with worm compost
- squished a bunch of the aphids (not my thing, but worth a shot)
- added local flowering plants to attract natural enemies
- added other flowers like common marigold and a ladybug flower seed mix
- led the rose plant to the front of the balcony
- added two hedera helix plants in the hopes they'd grow into a sort of frame around the front, but they're not doing much yet
- bought and spread out ladybug larvae multiple times over the past few years
- added two bee/insect hotels
- filled a pot with leaves and placed it upside-down on a large planter, hoping to attract earwigs and other aphid enemies
- added a ladybug hotel; a wooden box with horizontal slids, filled with leaves
The ladybug larvae help a little, but the problem with an open balcony is that eventually they fly away.
Effects of plants on attracting enemies and repelling aphids
I've been trying to attract natural enemies like ladybugs and hover flies by adding flowering plants, but it's not working.
This year I've had about half a dozen marigolds flowering, and a few other plants, but they don't last long because of the aphids. The rose plant and white grape plant are also suffering from white fuzzy aphid-like bugs, shown in the photo, in addition to the green aphids.
Even the mint plants and rosemary, which supposedly aphids don't like, were attacked by the little green bastards.
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I'm running out of ideas.
I'm thinking of putting more native and local plants on the front of the balcony, but the way it's going now, I'm not sure if they would survive.
The lower half of the front is behind glass, blocking direct outside access to passing insects. Maybe it would help if I lead climbing plants along the front sides and the top? The challenge there is that it can get very windy, and this being an apartment building, I can't have plants escaping the balcony.
I'd prefer to solve this in a natural sustainable way, do I haven't used the soap option.
I can keep buying ladybug larvae, but that will get expensive with the amount of aphids every year.
Please oh wise internet, can you help me?
Good point. I've ordered lacewing larvae now, but if it happens again in the future, I'll check if there are any environment-friendly soaps.