Start early for a stress-free fall/winter transition
Your pond plants have grown lush throughout the summer, your fish are thriving and eating heartily. Late-summer heat holds most of the country in its grip. But soon, as days shorten, the water temperature in your pond will start to cool. As your pond water temperature moves from the mid-70s to the mid-50s, it is an excellent time to winter-prep your pond plants and fish.
Countdown to late fall
Follow these four steps to transition your pond from late summer through fall and then to winter.
Clean - Falling leaves from nearby trees and bushes, as well as leaves from your pond plants, can quickly build up on the bottom of your pond. Settling to the bottom, the decaying vegetation can increase levels of dissolved organic compounds (DOCs) and rob water of oxygen, stressing your fish that are already struggling to deal with fall temperature swings. During late summer and early fall it is important to remove as much material from the bottom of your pond as possible. Drape a
pond net over your pond to prevent the majority of leaves and twigs from getting into the water in the first place. Your pruning,
dip net or
vacuuming efforts will take care of the rest.
Repotting pond plants is not just for spring. Perform this task in the fall to divide and store non-hardy plants. Many plants such as water iris, and submerged marginal plants can be divided successfully and repotted throughout the mild weather of early fall. However, it is best to repot water lilies and lotus in the spring. If you decide to repot plants during fall, do it as soon as possible. This will allow sufficient time for them to adjust before winter dormancy.
Prune - Prune long-stemmed, "leggy" plants to improve their appearance and encourage growth. By thinning and shaping, you make way for new growth, and more importantly, you prevent fallen leaves and stems from decaying in the water. Remove old water lily leaves by pinching them at the base. This promotes new growth. Use hand shears to remove yellowing and withered leaves from subtropical and marginal plants. You can also trim away excess root growth to "clean up" the planting baskets. Do not prune the small, emerging leaves at the base of plants. This new growth is vital to the health of the plant.
Feed - Mid-August through early September is a good time to
feed your pond plants supplements with micronutrients. These additional nutrients will build up energy reserves for the winter. Stop feeding when the water temperature cools below 60°F and leaves begin to die back. At this point you want to allow your plants to go dormant naturally.
Things that should not wait until the snow flies:
Bring fish in - If you plan to move your fish indoors for the winter, monitor water temperatures with a
water thermometer. Fish become stressed when exposed to rapid temperature shifts greater than 4-5°F. Bring your fish indoors for the winter, before water temperatures fall below 50°F, or earlier if your pond is not well insulated.
Make space for your plants - When the average water temperature is below 50°F, or before the first hard freeze, place hardy pond plants deeper in your pond and bring subtropical and tropical plants indoors. Plan ahead and find space for plants indoors. Have containers ready and immerse their roots in water. Bring plants indoors and keep them near a bright, sunny window. These subtropical and tropical plants will need heated water (at least 70°F) to overwinter successfully. Do not fertilize these plants during this period.
Pond maintenance is easier and more fun when done at your own pace, rather than under the pressure of a freeze warning. It's never too early to make pond winterization plans.