At 3,500 to 4,000 feet the first hard freeze arrives weeks earlier than it does in Charlotte, and the window for getting a pond ready is correspondingly shorter.
This is what we tell our own clients. If you'd rather do it yourself, do it with this — we'd genuinely rather you did it properly than not at all.
Netting goes on before the leaves drop, not during
The single most common mistake. Netting stretched over a pond that already has three weeks of leaf fall in it traps the problem instead of preventing it.
Leaves that sink break down over the winter under the ice. Come spring the water is stained, the gravel is packed with muck, and the biological filter is fighting a load it was never sized for. Most of the work in an expensive April cleanout is October's work, done late.
Fish stop eating before you think they do
A koi's metabolism follows water temperature, not air temperature. As the water drops toward the low fifties they need a wheat-germ based cold-water food, and below roughly fifty degrees they stop digesting properly and should not be fed at all.
Feed a koi protein it can't digest going into winter and it sits in the gut. Get a cheap thermometer and put it in the pond — guessing from how the air feels will have you feeding weeks too long.
Pumps: pull it, or run it
Both work. What doesn't work is a pump running in a way that supercools the water or drains the pond through an ice dam at the waterfall.
If you pull the pump, store it somewhere it won't freeze — a bucket of water in an unheated garage is fine, and letting the seals dry out is what usually kills them.
If you run it through the winter, watch the waterfall for ice building up and diverting flow over the edge of the liner. That's how ponds empty themselves in January.
Keep a hole in the ice, and don't make it with a hammer
A sealed pond builds up gases from decomposition with nowhere to go. You need one opening.
A floating de-icer or a small aerator will hold one. Never break ice with a hammer — the shockwave travels through the water and can kill fish outright.
What we do on a winterization visit
Netting fitted before leaf fall. Debris cleared from the bottom. Pump pulled or repositioned, and the plumbing drained where it needs to be. Filters cleaned and shut down or set for winter running. Water quality checked. Fish moved onto cold-water feed or off feed entirely, depending on temperature.
Fall winterization is $300. Heavy debris and netting on larger ponds are quoted on site.
When to book
At High Country elevation the first hard freeze usually arrives in October, though it varies year to year and with your elevation. The work wants doing before it, not after.