Gardening tips for November 2026

Pond Special

The flower garden and kitchen garden are taking a break right now; they plan to return in December. This doesn’t prevent the relentless need for clearing leaves or mulching the borders and spare a thought for all those garden tools. As the winter approaches and their use declines, now is a good time to consider a spot of maintenance. This is particularly the case for the lawn mower. It may not have seen much action throughout the summer but a good clean up and oiling will work wonders, especially as we all forgot to do it last year.

Ponds

One of the most common and less appealing aspects of owning a garden pond is the accumulation of algae, the usual suspect being blanket weed. Just keeping this one troublemaker at bay can help the appeal of a pond but there are other nuisances such as duck weed, green water and poor water quality. Spring is the time when problems tend to start, when brighter and warmer days stir the culprits into action. To get ahead of the curve (yes, I did use to work in an office) autumn is a good time to tackle some of these problems, aiming for clear water just in time for the water to freeze over in our upcoming harsh winter (according to El Niño and various news outlets). So, while you can still gaze lovingly at your reflection in the surface of the pond and want to improve its appearance (qui est of the pond) here follows a few suggestions on how to go about it.

Blanket weed – usual causes are fish waste, uneaten fish food, decaying leaves, dying pond plants, sludge on the pond floor, fertiliser washing in from surrounding borders, organic debris trapped inside filters or pipework.  Control consists of:

• raking out as much blanket weed growth as practically possible and leaving it in a pile next to the pond so that any trapped wildlife can return to the pond. Ideally the chosen spot should not allow water to run out of the pile of weed and back into the pond.

• to control regrowth, use a commercially available and natural blanket weed treatment. Make sure it is wildlife friendly.

• install a filtration system that includes a UV light or check that a UV bulb, if already installed, is still working and if not, replace. The manufacturers of the UV bulbs recommend replacing every year. I replace when the bulb has given up, they can go on for years and still be effective.
  

Green water – another algae problem, but one that should disappear quickly if using UV light inside a pond pump. The main cause in excess nitrates in the water. Nitrates form naturally as left-over fish food, fish faeces and dead plant material decays. Nitrate test kits are widely available and very simple to use, but often simply clearing out fallen leaves, cutting and discarding dead water-plant foliage and avoiding over-feeding your fish can make a big difference. Ensure fertiliser from surrounding flower borders or lawns can’t get into the water. UV light is really the game changer for green water, so installing a water pump/feature with a built in UV light is the most effective remedy.

Duck weed – More of a nuisance than a problem, however, a total covering of duck weed can be useful as it soon gets rid of blanket weed! Duck week is easily controlled using a net to skim the water surface to remove. This does need doing regularly as just one minute duck weed plant can multiply in a few weeks to recover the pond surface. There are commercially available and aquatic safe herbicides to eradicate duck weed. I’ve not used them, preferring instead my trusted fishing net; if anyone has experience of using this type of herbicide please comment via our website.

Water quality – this is mainly affected by leaves falling into a pond eventually sinking, then rotting, releasing nitrates that encourage the growth of algae that in turn reduces the levels on oxygen in the water. This is where marginal plants such as water lilies come in very handy as they absorb nitrates, however, the leaves and flowers still need removing as they get past their best as they will return nutrients to the water as they decompose.

Sounds like a pond pump with the appropriate filtration system including a UV filter could be the answer to most pond problems, this being the case the pump will need to be adequately maintained. Now is a good time to clean the filters and replace the UV bulb if needed or to install a pump to start getting the water into shape ready for the spring.

If all of this sounds very anti algae, one can always embrace the green stuff and join the British Phycological Society.

Keep gardening, Richard Haigh EGRGA Communications