As this year’s scorching summer reaches its peak, a 10-minute “pick-me-up” this weekend could help keep your hanging baskets and windowboxes from flagging.
Unlike plants in open ground, which usually has a stable level of moisture and nutrients, plants in small containers experience wide fluctuations due to their smaller volume of growing media. In the case of nutrients, most potting composts only contain enough soluble fertiliser to support about six weeks of healthy growth, meaning containers that were planted up in the spring will be running low come July.
As most summer bedding plants are subtropical or tropical in origin, they will continue to grow right up until the first frosts, offering continual flowers instead of the two-week flush of many temperate species. However, this also means they are far hungrier for water and nutrients, making them more vulnerable to lack of water and fertiliser than other plant types. Fortunately, with a few simple tips and tricks, you can help support this growth, keeping them looking their very best.
The first step is to get out some sharp scissors and take out any growth that has yellowed or crisped up, as well as any spent flowers (“deadheading” in horticultural speak). In many species hormonal signals are emitted as flowers start to fade, causing the plants to cease production of new buds in an attempt to redirect precious energies from flower production towards ripening the seeds. Snipping prevents this hormonal trigger, giving you loads more blooms over a far longer period.
Second, give your plants a really good drench with a liquid fertiliser (I use an organic seaweed-based feed) to help replace nutrients that have been lost from the growing media over the season. I am a big believer in watering plants really thoroughly less often, rather than a daily light spritz, as it ensures water penetrates right down to the roots instead of sitting on the surface where it may evaporate off. For best results repeat this feeding every two weeks. If you are a non-organic grower, use slow-release fertiliser granules, which slowly emit feed over six months, meaning you can slash the amount of work needed. While these are best incorporated into the growing mix at the beginning of the season, it is not too late to add some now to the surface and gently mix them in with a trowel.
Third tip: I add five 300g soluble aspirin tablets to every 10-litre watering can full of soluble fertiliser mix. This may sound mad, but is based on good evidence: aspirin is a compound based on a hormone found naturally in plants called salicylic acid, which helps regulate their responses to environmental stress. Dilute aspirin solutions have been shown to help make plants more resilient to drought, heat, cold and even some pests and diseases, and it is extremely affordable and easy to administer, too.
All in all, these three treatments shouldn’t take more than 10 minutes and will probably result in a significant improvement to the health of your plants, keeping your garden looking lovely.
Email James at james.wong@observer.co.uk or follow him on Twitter @Botanygeek
