Too much rotting organic matter, such as leaves and other dead vegetation, resting on the pond bottom reduces water oxygen levels and is detrimental to pond wildlife. The steep bank on the left contributes to the pond high nutrient levels, too. However, some dead organic matter is useful as a substrate for plants and invertebrates. The best time to rake out a pond is autumn, before wildlife and minibeasts go into hibernation and after plants have finished flowering. Dredging’s are best left on the edge of the pond for a few days to allow minibeasts to escape back into the pond. Encroaching vegetation can become a problem, but it can be pulled out or divided; this should be done in autumn.
Making sure there are sufficient logs, stones and rough vegetation at the pond edge, is also important, especially during winter when these will be used as hibernation sites by frogs, newts and others.
I’ve raked out approximately half the 600mm deep GCN pond so far, and my debris pile is already 2 metres high X 3 metres wide and 4 metres long, consisting of rotting leaves, branches, twigs, weed and silt. I’ve left some oxygenating plants in place, but mostly the pond is clear of vegetation. I have plenty of oxygenating plants available in the Swamp to transplant later if necessary, but I will wait until the end of this year’s growing season to see how the pond has responded to raking. Plants are needed to consume excess nutrients and oxygenate the water.
Duckweed and watermeal are found in nutrient rich ponds, those where a buildup of leaves on the bottom creates stratification. Black, smelly ooze is a primary food source for duckweed and nutrient reduction will help control it, as will bubble aeration. On a windy day, the duckweed blown to the northern end of the GCN pond where it can be shovelled or scooped out. Duckweed and watermeal are very prolific plants, able to double their growth every one to two days.
After raking out the easy section, I’m now clearing a 5 metre long choked section at the south end of the GCN Pond.
Each year bulrushes, yellow irises and reed grass creep further along the pond. My plan is to reclaim a five metre section this year by raking out some of the plants that choke the pond. The problem is that I would need a donkey pulling on my long handled jumbo ditching fork to stand any chance of raking out these plants, and I don’t have a donkey. I do have a sod cutter, though. The sod cutter works vertically and horizontally to cut the root systems into manageable pieces, allowing me to rake them out with the ditching fork.
An intermittent mournful groaning and wailing sound has interrupted my otherwise tranquil time working at the pond. It has baffled me for days. It happened this afternoon, so I set out to track it down. I was beginning to suspect someone was playing a trick on me. The culprit turned out to be a gate post. When the gate was open, gusting winds rushed through the rectangular bolt slot and exited through a small hole in the top of the post.