Ask the Plant Doctor! How to prevent snails in your garden

Goji berry does not require a lot of water or fertiliser. Photos: 123rf.com

Do you have a question about plants or how to maintain your garden? Send your questions to the Plant Doctor! Email your questions to [e-mail] with "Plant Doctor" in the subject field. Questions may be edited for brevity and clarity.

1. How do I grow goji berries? I am able to get the seeds sprouted, but they won’t grow any further even though I have tried to give them the best care, such as watering them and protecting them from strong sunlight. – Kong YT

While goji berries (Lycium barbarum) generally require low maintenance once they are well-established, they are nevertheless sensitive to over-watering. Over-watering could harm your plants’ growth, particularly seedlings.

Therefore, it is critical to ensure your goji berries are planted in soil that drains easily. They can tolerate poor soil conditions but not waterlogged or very wet soils. If you are cultivating them in pots, opt for a potting mix or for soils low in clay, as soils high in clay tend to retain too much water. Always check the soil moisture before watering; only water when the top few inches of soil feel rather dry to the touch.

To check if over-watering is the problem, gently extract the failed seedlings from the soil, being careful to avoid damaging the roots. Upon examination, if the roots are mushy and emit a foul odour, it is likely that over-watering has induced root rot.

Goji berries also require little fertiliser. As with watering, avoid over-fertilising or “experimenting” with various fertilisers in rapid succession. Instead of chemical fertilisers, consider using composts or organic fertilisers.

They offer a lower, slower and more controlled release of nutrients, as compared with the more highly concentrated and faster-acting chemical fertilisers.

Sprinkle egg shells around your plants to prevent snails from gnawing on their leaves.

2. My apartment is on the 8th floor, but I found snails in my balcony garden. How did they get up there? And what can I do to prevent snails from eating up my plants? – Shannon Lee

Snails are good climbers and climb up walls and across many types of surfaces.

Unknowingly, you may also transport them on plants or in soil introduced to your apartment.

There are numerous strategies to keep these critters at bay.

You can create a physical barrier around your plants by using copper tapes or finely crushed eggshells. You can also apply Diatomaceous Earth (DE), which can be bought online. DE is a natural product, comprising fossilised remains of tiny, aquatic organisms called diatoms. Snails dislike crawling over these materials, as doing so would injure their soft bodies.

Never use table salt. While effective in killing snails, salt is equally harmful to soil health.

Manual removal of snails is also effective, especially for small garden spaces. Opt to do this in the late evenings or very early mornings, as snails are mostly nocturnal and typically hide during the day.

Regularly clearing away dead leaves and other plant debris can also eliminate potential hiding places for the snails.

Dr Christopher Teh heads the Dept of Land Management, Faculty of Agriculture, Universiti Putra Malaysia and coordinates the Healthy Garden series. The views expressed are entirely his own.