Growing season's almost over. Have you planned your cover crop yet?

Whether we are ready or not, the end of the growing season is fast approaching. The days are getting shorter by the minute (actually by more than five minutes each and every day now) and that means the end will be coming. In normal years we can count on a killing frost in mid to late September. What this means is now is the perfect time to plant a cover crop in your vegetable and flower gardens and large containers.

Cover crops are plants grown toward the end of the season to benefit the soil. They include legumes, oats, ryes, buckwheats and even daikon radishes. The legumes provide the soil with fixed nitrogen. The rye and oat roots create soil structure, suppress weeds and impart carbon as well as feed the soil food web. The daikon radishes are killers at breaking up compacted soil.

Farmers have been using cover crops forever, but the idea of using them in home gardens and particularly in containers is just now catching on.

Here in Alaska, I would stick with the annual ryes, rather than the cereal ones. In addition to being tender to frost, the annuals are allopathic to weed seeds. And, the cereal ryes will start growing again in the spring, which we don't want.

Oats and an annual field peas are often a recommended combination. Both will excel here.The peas provide nitrogen by fixing it from the air. They use the oat leaves to climb on. The oats provide good root mass and add lots of organic matter when they are killed off by the frost.

Buckwheat, too, can be added to your soils and will help control quackgrass, a real problem in our gardens. Buckwheat is not a wheat grass. It has broad leaves and it is a very fast grower and may provide little, white flowers before the plants are killed off by the cold. They are actually very pretty.

Next, there are lots of different clovers available for adding nitrogen to the soil. Here you want to make sure you are adding an annual and not a perennial clover. Crimson clover has red flowers that are really quite a sight in a fall garden.

Often you will find vetch in the mixes. This is usually a crown vetch. I would avoid them so they don't spread if seeds develop before the plants are killed.

How much seed should a home gardener use when applying a cover crop? Plan on using 8 ounces or so for every 100 square feet of garden. You can do the math if your beds are larger. Whatever you do plant will help. You will probably find the cost of the seed is what will prevent you from overdoing it — though it is hard to plant too little or too much as every germinated seed helps.

The real question is where to find seed. As always in Alaska, first look for seed locally. Nurseries are starting to carry these crops in small, home-size garden batches. Larger quantities can be purchased at a seed and feed store. They may break up the farmer-size pound bags and sell you less or you could buy big bags and split up the seed with your friends.

You can also get this seed via the internet. Try Territorial Seed, Terroir Seeds, Peaceful Valley or Johnny's Seeds. If you are going to order, you'd better hurry, however. Now is the the time to act, not two weeks before a frost. This is because the recommendation is to plant these crops about 4 to 6 weeks before the first expected frost. You can broadcast them over empty (fallow) beds and containers or use them in between existing plants. They readily germinate, and you only need to scratch the soil surface a bit and broadcast the seeds. Your regular watering routine — or nature's this time of year — will suffice so other than the effort of buying them and tossing them out into the soil, there is not much work involved.

Once the hard frosts hit, the plants die. The tops become mulch and the roots start to decompose. Next spring, just plant away, and your crops will be the better for it.

Jeff’s Alaska Garden Calendar

Recycle Pots: Saturday, Aug. 20, is the annual garden pot recycling event at the Alaska Botanical Garden. From 10 am. to 5 p.m. you can bring pots to the garden and leave them there for recycling thanks to WestRock, Alaska Waste, Faltz Landscaping and Nursery and, of course, ALPAR and the garden. The pots must be sorted into one of two groups: No. 2 HDPE pots and trays or No. 5 PP and No. 6 PS and any unmarked pots, cell packs and trays. It is really easy and you will really be helping out the environment. In years past literally tons of those flimsy pots and trays have been collected.

New Lawns: It takes about 21 days for lawn seed to germinate. If you are going to put down seed, the next week or so is the time to do it.

Weed eaters: Come on. Just because it is the nearing the end of the season doesn't mean you shouldn't keep the place looking neat.