When to start planting in the garden
April 28, 2022
By Blythe Carter
Warm spring sunshine makes us all restless, especially when our bare gardens sit there staring back at us, gently mocking! Which begs the question: when can you start planting?
The official last frost date for the Haines town site is generally considered to be around May 15th (although the internet gave me wild results from May 5th to May 31st). Old school wisdom says to pay attention to the trees. When the leaves start to burst forth in bright green, then you can start planting. Or when the first dandelions start to bloom. All these signs work well and given some TLC your plants will flourish, but you can often plant earlier.
It’s all about night time temperatures. A frost can kill tender plants or severely stunt them, so night temperatures must be consistently above 40 degrees — which, if you’re wondering, is not quite yet. Anything planted out before this, assuming it survives, will just sit there and shiver.
While today’s weather forecasts are pretty accurate, they may not be correct for your microclimate, which may be warmer or colder than the weather station’s location. Instead, purchase a minimum/maximum thermometer. I have several units with wireless sensors that can be placed outside or in my greenhouse with the reader sitting on my counter. I check each unit in the morning to see how cold it got the night before. When the temps have been above 40 for a week, and the forecast looks good, you can start planting cold hardy crops. But keep an eye on the predicted night time temperatures and have a cover ready just in case.
There are some work arounds that can get you digging in the dirt a little earlier. Some plants, such as spinach and the cabbage family will do okay in cooler temperatures (high 30s), under covers or clear plastic. Make sure to protect broccoli, cabbage and cauliflower and everything else in the cabbage family from root maggots. Secure the edges of your covers and seal off any holes so the flies (which lay eggs that hatch into maggots and feed on your plants’ roots) can’t get in.
Potatoes and snap peas can also be planted when temperatures are in the high 30s but they must be mulched to protect them from light frosts. Both will naturally emerge when its warm enough for them to prosper.
Zucchini, beans and other warmer weather crops will resent and possibly die in any temperatures below 50 degrees. Plant these under row covers when the temperatures are cooler (in the 40s) and they will reward you with amazing growth and early crops.
And remember, there’s a lot you can do before planting including turning garden beds and mixing in manure and compost, putting in that new bed or repairing old ones. How about attacking those stubborn weeds — the more you remove now the less you’ll have later and they’re much easier to pull before they’ve put on any growth. Now is the time to prune away winter damage from berry and ornamental bushes and to manage your fruit trees!
Warm wishes and happy gardening.