Tactics to extend the season
The main purpose of koi ponds and water gardens is to see and enjoy the inhabitants, fish, and plants. This is true whether you design/build ponds, sell plants, or maintain ponds. Whenever you can maximize the growing season, pond inhabitants show off better, pond owners are happier, and your pond business is more prosperous.
Most people think weather conditions are based only upon location and the seasons, so nothing can be done about them. In reality, there are many ways to control the light and warmth a yard and its ponds actually receive. Being proactive (aka bluffing Mother Nature) has benefits for all pond inhabitants. As we Southerners know, plants and koi grow when it’s warm. So gaining additional growing time can make a big difference, literally and figuratively.
Nature regulates aquatic plant performance with two things: light and water temperature. Since both are direct results of how much sunlight reaches the pond water, our bluffing strategy has two components: maximizing sunlight for the inhabitants and retaining heat in the water. When we master this game before the season starts and as it ends, the viewing and growing season gets longer in early spring and late fall, sometimes by several weeks.
A microclimate results when local conditions vary from the surrounding region. (For example, thanks to their microclimate, my neighbor’s garden with a sunnier exposure grows better roses than we do.) Factors that influence a microclimate can be natural or man-made and their importance should not be underestimated.
It is possible to intentionally create a microclimate in order to extend optimum conditions for pond dwellers. Existing surroundings can be modified and artificial assemblies can be constructed. The dual objectives are to maximize sunlight on the pond and provide shelter from prevailing cool winds.
Variations in the duration and strength of solar radiation cause seasonal temperature fluctuations, which obviously affect pond temperatures. In addition, day length is usually the most critical factor for regulating plant growth, flowering, and dormancy. (Winter days can be seven hours shorter than summer days, depending upon latitude.) So besides contributing more heat, lots of sunshine is also necessary to push plants out of the winter cycle and into their growing season.
Light intensity on a pond surface varies with elevation, latitude, season, and weather conditions. And even in gin- clear water, the amount of sunlight plummets as you go deeper. Of course, in bourbon-clear or algae-tinged water, the effect is even more pronounced. Determine the sunniest spots in the yard and in the ponds by checking for patterns of sun and shade throughout the year. Survey any shadows cast by plants, houses, or fences and pay special attention to sunny locations in the spring. (Websites and apps about landscape photography or gardening include data on daylight length and sun angles.)
When designing a pond, orient it toward the south or southwest and take your sun/shade survey into account. If that is not practical, keep the pond as open as possible to available sunlight. Create a sunny spot for water lilies even when the sun is lower in the offseasons. If necessary, accentuate winter sun by trimming branches and strategically planting deciduous trees. That will let sunlight penetrate in the cold seasons but provide shade during summer.
Another way to maximize the solar radiation reaching ponds is to change the height or location of fences and overhead lattices to take advantage of the sun’s lower angle during early spring. (When carefully planned, garden structures can still provide adequate shade during the summer when the sun is higher in the sky.)
Controlling undesirable winds creates a warmer microclimate, a major factor for a more comfortable yard and more productive garden. It also helps with the ambient pond temperature and reduced cooling of the surface water.
Cold water is heavier, so when water cools it gets denser – until it reaches 40°F. Below that point it becomes lighter, which is why ice floats. As temperatures rise in the spring, the surface water becomes warmer and lighter while the cooler, denser water forms a layer underneath. Maintaining the warm top strata is crucial to get a jump-start for plants.
In the spring, obtaining and retaining pond heat is important, especially at night when most of it is lost. Structures and plantings can protect against cold blasts, which usually come from the north. Walls and fences can also be painted a light color to generate radiant heat. Contrary to what most folks think, a solid barrier provides minimal wind protection. The wind simply blows over it and continues a few feet downwind. However, ventilated screens or fences disperse and slow down cooling winds. Compared with the effect of a solid fence, they are much more effective at retaining the heat generated within the pond.
So you see we’re not really trying to fool Mother Nature, but rather to adapt her own strategies and produce a longer season. To create a warmer microclimate we maximize her most precious wintertime commodity (sunlight) and minimize the most undesirable (wind). Our goal is to get light underwater to the aquatic plants and trap heat in the pond.
With a little manipulation, we can gain several extra weeks of growth for our fish and aquatic plants. So, whether you design a new pond or maintain an existing one, create a better and longer growing season for the pond dwellers. They will be happier and so will the pond owners.
9 Ways to Bluff Mother Nature and Win a Longer Water Lily Growing Season
Increased daylight and warmth are Nature’s signals telling plants and animals to grow. To jump-start aquatic plants, maximize the amount of light and heat at their crowns (growing tips) before the season begins … and at the end.
1 Design water gardens in the warmest, brightest spot in the yard, ideally with southern or southwestern orientation.
2 Place plant containers very close to the water surface, in spots where the sun is strongest and the water temperature highest. Place the water lily crown about 3-4 inches below the water surface. Once the plants get good growth, gradually lower them or move to them shadier areas.
3 Prop up pots on black file crates. Bricks or concrete blocks can also be used with precautions. Protect the liner under the bottom blocks. When fish are present, make sure cement is weathered to prevent leaching. Remove the blocks or wrap rough edges during spawning.
4 Cover the pond surface with bubble wrap or styrofoam in evenings to retain heat. Or make a temporary, inexpensive greenhouse over the pond from arched PVC pipe covered with clear plastic sheeting.
5 Pre-start tender tropical lilies in a small outdoor pond, tank, or tub. Place it in full sun where you can control the water temperature. If possible, use either an aquarium or stock tank heater, depending on the pond’s size.
6 Create a mini-pond in the basement, with artificial lights and heaters. Or make use of a heated jacuzzi during the off-season when no one is using it.
7 Borrow a friend’s greenhouse to keep plants for a few weeks before the season starts. This will help the plants warm up earlier and get a running start on the growing season.
8 Keep some tropical marginals indoors over the winter. Since they won’t go dormant, growth starts earlier in the spring. Dwarf Papyrus and Umbrella Palm are two that make great houseplants. Remove all insects before bringing them inside, keep then in a bright spot, and use deep saucers to keep them moist.
9 DO NOT hurry the spring planting process. Putting tropical plants into the pond when the water temperature is too low can send them back into dormancy. Then they take extra long to start growing. Tropical water lilies must have constant water temperatures of 70-75°F.