Why have a garden pond?
Garden ponds are wonderful haven’s for wildlife. They can provide beauty and interest in your garden and if designed correctly can make a real difference. You may not get endangered species in your pond, but it can be a real refuge for many others. Frogs may be doing better in suburban gardens than in the wider countryside. They are valuable for other wildlife too. Birds may drink and bathe in the shallower margins, or eat the autumn seed heads of reeds. Insects feed on exposed mud, and at night, bats hunt for flying insects over the water. If you want to see plenty of wildlife close to home, put in a garden pond!
Designing your pond
You need to think carefully about where you want your pond to be, you should therefore mark out your pond before you start to dig. If it’s in sight of the house, you’ll be able to watch birds, bats and other visitors. If the pond is away, it may attract more timid species. You should aim to have part of the pond in full sunlight. This allows the water to warm up quickly in the spring, so encouraging plant growth. Avoid having it directly near a tree as the roots may pierce you liner or the pond may get full of leaves.
When to build
You can make a pond in any month but early autumn is perhaps the most practical season, when the ground is neither too hard, dry nor cold.
Size, Depth and Shape
The size of your pond is up to you and your budget. The size of your pond should be in scale to the size of your garden, but even the smallest of ponds can be of great wildlife value. Garden ponds needn’t be deep, but for a wildlife pond they should be at least 40cm-50cm deep, but remember you will need to create shallower margins around the sides. This is probably the most important design element of the pond. Make sure you leave LOTS of shallow water shelf area at about 1-15cm deep, where water plants will flourish. The margins should be very gently sloping in at least some places, so the finished pond merges naturally into the land.
(Sussex Wildlife trust)
Filling your pond
Most people fill their ponds with tap water. This is easy but rather wasteful. Tap water also often contains high quantities of nutrients that encourage algal growth. The best possible source is rain water. If you have a water-butt you could fill up you pond using the rain you have collected.
Pond plants divide into several categories:
Oxygenators.are usually submerged plants.
Floating plants.The leaves of these plants float on the surface. Some of the plants may be rooted, but others float freely. The floating leaves provide shade for the water below, thus reducing build-up of algae. They also act as platforms for viewing, courting or mating for a variety of insects.
Emergent plants have erect stems and leaves, which emerge above the water’s surface. These are important for dragonfly nymphs.
Marginal plants need to grow at the shallow edges of the pond. Some need to be permanently in a few centimetres of water, while others will tolerate periodic drying out.
Marsh or bog plants are wetland plants that grow near the water’s edge. Their requirements vary from those that must be in permanently wet soil, to those which need moisture retentive soil, but do not tolerate being waterlogged.
Should I put fish in my wildlife pond?
Unfortunately, fish tend to dig up bottom-rooted vegetation and many will eat tadpoles and other pond creatures. If you regularly feed large numbers of fish, the nutrients added to the water will encourage green algae and blanket weed that can smother the whole pond in a very short time.
Can I plant exotic plants around my pond?
Exotic plants will not prevent many interesting native animals colonising your ponds, but plants long-adapted to conditions here normally support a greater variety of invertebrates. Wildlife ponds should contain mainly native plants, many of them very beautiful.
There are a number if plants that you should avoid completely as these can escape the confines of you garden and cause ecological damage to ponds and rivers through their ability to spread very quickly – even with the smallest fragment. Plants to avoid completely are; Fairy or water fern (Azolla filiculoides)
What can I do about the blanketweed/duckweed in my pond?
Blanket weed and Duckweed are natural components of pond communities. A build-up of blanket weed or duckweed tends to mean that there is too much fertility in the water. This could be due to the nutrients in the water supply, especially if tap water has been used. Another may be run-off from a fertilised lawn or flowerbed. If you can’t improve the water supply, there are other ways to reduce the problem. Remove all blanket weed with a lawn rake as it builds up, and compost it. Duckweed can be skimmed away. Immersing small bags of barley straw is an effective natural control for blanket weed, although it won’t provide more than a temporary fix.