As the weather cools, Alaska gardeners have some early tasks to complete before first frost

I wince every time my wife mentions the chill in the air in the early morning hours. First time I shrug it off, but by late August it is difficult to still assert we have plenty of gardening time left.

Nonetheless, I am not willing to set out what we all need to do before the first frost; I try to save this for after Labor Day. There is still time to coax a few more dahlia flowers, blue gentian hasn’t flowered and even though we already harvested our broccoli plants several times, there might just be enough time for a few more replacement flowerets to appear around the cut of the older ones.

By the same token there is still probably enough frost-free time to seed your lawn if you so desire. I am betting we have the 20 days it takes to germinate grass seeds before a frost, but even if we don’t, your efforts should show results by spring. And by all means, aeration of your lawns this time of year wouldn’t hurt either. Just don’t put down fertilizer, which will stimulate unwanted growth as we go into the dormant season.

This is the time of year I get complaints that people’s lawns are turning to moss. This happens to most lawns in Alaska, eventually. Personally, I love this turn of events. Moss is soft, green and beautiful. When I cut our front lawn very low mostly all that is left is moss, until the grass starts to grow back a week or two later. Still, if you want grass, you want grass.

To deal with moss, you need to raise the pH. Adding lime is an answer. However, I am no longer sure this is very effective as lime is chemically tied up in the first inch or so of your lawn’s soil and may not have the impact we want on the root zone. And, it takes several applications over a long period of time to move the pH back up to where it needs to be. Go back to the idea of aeration. If you want that lime to get into the root zone, it is this option or tilling the stuff under, which is not a practical solution. Repeat in the spring and see what happens.

Lime can be tilled or dug into garden soils, however. If you have moss in your garden beds, see if your local nursery can test the pH. If it is low, apply lime at the end of the season and work it in with a tiller or by digging and folding the soil over. Rototilling affects the microbiology of your beds, so only do so if you really, really have a moss problem.

Next, cool weather means leaves will start to fall in a few weeks. If you don’t have a compost pile, start one now. Your pile must be a minimum of 3 feet cubed. Do collect a few bags of grass clippings so you have some “green” material to mix in with the “brown” leaves. You need a 30-to-1 carbon-to-nitrogen ratio which is made by mixing one bag of leaves with one bag of clippings. Even though there is a chill in the night air, there will be plenty of microbial activity to start the composting process and it will continue all winter long. Turn your pile a few times and come spring there might even be some useable compost.


And finally, when it gets a bit cooler, it will be time to plant garlics. Now is the time to order or buy yours locally so you have it on hand to plant in a few weeks. There are two kinds. Hardneck garlics do best in our climate. Look for varieties Music, German White, Siberian, Chesnok Red, German Red, Russian Giant, Purple Glazer and Khabar, which have been tested and proven to do well in Alaska.

Jeff’s Alaska Garden Calendar:

Beer in the Alaska Botanical Garden: Thursday, Sept. 8 from 6-9 p.m. Craft beer and cider from local breweries, local food vendors Nonkie Be’s Cajun Faves, Salmon HookUp Truck, Wild Fork, Yeti Dog and Wild Scoops Ice Cream will be on-site with delicious food for purchase. Live music performed by Zen Trembles, lawn games and fire pits. Tickets are available at or go to

Flowers: Why not cut a few and take them inside to enjoy while you can?

Apple tasting: Free apple and fruit tasting on Sunday, Sept. 11, from 1–2:30 pm in the Anchorage Begich Middle School All-Purpose Room.

Jeff Lowenfels

Jeff Lowenfels has written a weekly gardening column for the ADN for more than 45 years. His columns won the 2022 gold medal at the Garden Communicators International conference. He is the author of a series of books on organic gardening available at Amazon and elsewhere. He co-hosts the "Teaming With Microbes" podcast.