Dreamy dahlias

Love dahlias? Discover a few tips from flower farmer and self-confessed ‘dahlia addict’ Jen Foster.

In the New South Wales Southern Highlands, Jen Foster’s love affair with dahlias led to her farming them organically and growing hundreds of different cultivars, including pompom, cactus and waterlily varieties. Here are a few of her top growing tips:

Dahlias love full sun. The national recommendation is to plant tubers in the first week of November, after the last frost. I plant mine in October so they’re flowering for my farm tours in February.
Soil quality is important, so check pH levels. You can buy testing kits at major hardware stores. A pH level of 6.5 is ideal – add lime or liquid sulfur to adjust it. If you’re having trouble getting dahlias to grow, you can do a soil test through an independent lab.
Dahlias love a rich, well-drained soil, so add lots of organic matter, such as cow or sheep manure mixed with compost.
Pull up any dahlias that are showing signs of disease, and get rid of insect pests using predatory insects (available online) or an organic insecticide or fungicide. If your dahlias have gall (a bacterial disease), remove the whole plant and soil around it, so it doesn’t spread to other plants.
When my plants are 1m tall, I strip the bottom third of leaves to allow better airflow and prevent any fungal issues. Doing this also gives nasty bugs less space to spawn themselves.