Winterizing Your Pond

Winterizing your Pond

Updated. Originally published December 6, 2019

Goldfish & Koi

Koi, goldfish, and gambusia will survive Texas winters without a heater. Avoid allowing the surface of the water to freeze solid. Toxic gasses will not be able to escape, and this can be lethal to your fish. The easiest way to prevent this is to float a ball in the pond. Alternatively, you can use a deicer/aerator and/or leave your water feature running 24/7.
If you have a stream or waterfall, check that ice dams are not forming. Ice dams can create a leak that will drain the pond if left unaddressed.

When water temperatures drop to 60 degrees, stop using high-protein fish foods and switch to a more easily digestible winter wheat formula. As always, only feed your fish what they can consume within 5 minutes. When water temperatures consistently reach 55 degrees, stop feeding the fish entirely. If fish are fed in their semi-dormant state, food will sit undigested in their body and can cause illness or death.

Fish will become lethargic and school together at the bottom of the pond. Don't worry! They just want to hang out in the warmest part of the pond. They will become more active as water temperatures rise in the spring.

Predators will more easily spot your fish as your plants go dormant and stop producing lush foliage. Consider giving your fish a place to hide by building “fish hotels” with cinder blocks. You can also use decoys or pond netting. Pond netting will prevent excessive leaf litter from building up as surrounding trees drop their foliage. Excessive leaf litter will contribute to water quality and clarity issues.

Aquatic Plants

Water Lilies: The last day to fertilize water lilies is October 1st. The growth tip needs to harden off before water temperatures become freezing. As our days become shorter and water temperatures decrease, you will see few pads and little to no flowers. These are typical signs of the plant going dormant. Trim unattractive foliage as needed. Tropical water lilies can be dropped to the deepest part of the pond where the water temperatures are higher. Remember to raise them to the shallows of the pond in March.
You can begin fertilizing your water lilies again when water temperatures reach 60-70 degrees and new pads begin to reach the surface of the water. It will be necessary to repot your water lily in April or May. Water lilies are vigorous growers and quickly become root-bound in one growing season. If pushing the fertilizer tablet into the soil is difficult, your water lily likely needs to be repotted. Other signs include fewer pads or flowers throughout the growing season.

Lotus: The last day to fertilize lotus is September 1st. Trim unattractive foliage as needed. Never trim lotus stems below the water level. The stem acts as a straw pulling water into the tuber and will rot/kill the plant. Lotus typically need to be repotted every 2-3 years. Repotting should be done in January or February if needed. Generally, lotus will grow the first year with few if any blooms. In their second year in the pot, they can put on quite the flower show. The next year they will be rebound and need dividing and repotting. It's best to begin fertilizing lotus when the leaves stand above the water. Lotus are heavy feeders and can have their fertilizer rate doubled until the hottest point in summer. The plant will go semi-dormant in Texas summers and can be moved to the shade to maintain the best possible foliage.

Marginal/Bog Plants: The last day to fertilize is October 1st. Iris, in particular, should be fertilized if you want a beautiful show of flowers by spring. As foliage becomes unattractive, the plant can be cut back - 3’’ above the crown of the plant. Bog plant root systems should completely submerge below the water's surface from October 1 - March 1st. The water will insulate the root system from freezing air temperatures. Most bog plants will become root-bound in one growing season and should be repotted yearly, though they tolerate being root-bound more than water lilies. You can begin fertilizing bog plants on March 1st.

Algae

Algae growth is dramatically reduced from late fall to early spring. You will likely not have green water issues, but filamentous algae (“String Algae”) will continue to grow. We always recommend using natural solutions whenever possible.

Barley (bales or extract) naturally inhibits algae growth and can be used year-round. Bacteria is an excellent product for preventing green water. In addition, bacteria will also reduce sludge and foul odors. Bacterial growth is correlated with water temperature. Use a bacteria labeled for cooler water temperatures. Most of our bacteria will work until water temperatures hit 50 degrees.

Trees and other deciduous plants dropping leaves in or around your pond will contribute to water quality and clarity problems. The leaves will break down and release toxins and nutrients in the water. The toxins will cause harm to ornamental fish, while excess nutrients can contribute to algae blooms. Using bacteria will help keep sludge in check while converting the toxins into plant-available nutrients. Pond netting will prevent leaf buildup.

Materials for Winterizing:

• Bacteria, Barley, and or Algaecide

• Floating thermometer

• Pond Netting

• Wheat formula fish food

• A ball, Aerator, de-icer, or pump (something to prevent the water surface from freezing solid)

Pro Tip for koi owners:

Most pond owners feel guilty for not feeding their fish in the winter. As a reminder, you would do more harm than good to feed them when water temperatures drop below 55 degrees. If you're not already adding Montmorillonite clay to your pond, consider applying it this winter. Rubber-lined/concrete ponds lack the micro-nutrients and minerals that would be in natural habitats. The fish may not eat this time of year, but they are breathing! The Koi will breathe in the minerals found in montmorillonite (60 bioavailable minerals and trace elements, including calcium, magnesium, potassium, sodium, and iron). The clay will aid digestion, increase their immune system, improve overall health, and define and brighten their colors. Montmorillonite clay is a negatively charged flocculant and binds to positively charged toxins, heavy metals, and phosphates. The clay will almost polish the water. Overall, Montmorillonite clay improves water quality for fish and other inhabitants. You can apply the clay directly to the water or roll your fish food into it!

Cold fronts bring cooler weather, but they also bring on hidden dangers when massive amounts of raindrops in our ponds! Our water here in Central Texas is incredibly hard; that means a large amount of dissolved minerals exists in our water. That’s why you get ‘hard-water spots’ or that white chalky substance left behind by evaporation. This includes two specific compounds: Sodium Carbonate and Bicarbonate. These compounds work in your pond as a pH buffer, keeping our water at a steady pH of 8.4 throughout the day. When the pure water from heavy rains wash all of the mineralized water out of our ponds, pH can begin to fluctuate wildly, possibly leading to an unexpected loss of fish. If we have heavy rains this season, it may be a good idea to do a 10-20% water change soon after to replace lost minerals. Don’t forget your dechlorinator!