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I know we make a big deal over the appearance of those squirrel ear-sized leaves, just like everywhere else. The thing to remember, however, is that here we also have to contend with soil temperatures.
I’ve written about this before, because best practices suggest it is always a good idea to wait until soil hits the proper temperatures before planting seeds. The goal is to plant at temperatures that will ensure the quickest germination. You do not want your seeds sitting in damp soil and rotting instead of growing.
I happen to have a soil thermometer because I was given a couple at a garden writers conference. You probably don’t. You can check to see if your kitchen thermometer has the appropriate scale with low temperatures, or get one from your hardware store or via the internet. They are not expensive.
In general, we want soil temps to be between 65 and 75 degrees Fahrenheit, and yes, our soils do get that warm even if our air temperature doesn’t. This is the ideal range, but individual seeds will germinate at lower temperatures. In some instances, lower temperatures will mean more days for an individual variety of seed to germinate, and the warmer it gets the quicker they do so. Check out the chart at the University of California to get an idea of this relationship.
If you study the chart, you can get an idea why some people dare to plant seeds in early May and why the traditional date for planting outdoors here in Southcentral Alaska is Memorial Day weekend. It all has to do with soil temperatures.
You can warm your soils a bit by using raised beds, or with plastic sheeting. Most would automatically use black plastic, but it turns out using clear plastic heats up the soil quicker and to a higher degree.
I know, plastics. Slap me. We really have to get rid of it, not add to the overall problem plastics cause. A better idea, therefore, is to either be patient and let the soil warm on its own or try something else.
That something else could be warm water. For a long time I advised getting some source of hot water to mix with the 40-degree tap water we use on our gardens. Ideally, you put a “Y” on the hot water inlet to your washing machine. If you can’t rig a system using your washing machine hot water tap, consider using a bucket or watering can filled with warm water.
Of course, planting the right seeds is key. That is why we don’t grow corn as a matter of course and why Alaskans tend to stick to cole crops outdoors and use an indoor greenhouse for tomatoes, peppers and even corn.
I know some are tempted to use a rototiller or double-dig garden beds and fluff up the soil, partially to warm it. You might get a few extra days, but the damage you do to the soil food web, especially the fungal network, makes this a no-no.
I am very happy those birch leaves appeared. The fact that they are now much bigger, however, gives me all the hope I need that our soils are almost there, temperature-wise. Maybe we should add a connection to their reaching full size and soil temps.
Jeff’s Alaska Garden Calendar:
Alaska Botanical Garden: Lots of you have joined and can skip over this next stuff because you are ahead of those who did not. Members are getting early-bird announcements and nonmembers are not. Join, for goodness’ sake.
Mother’s Day at the Garden, Sunday, May 11, 10 a.m.-4 p.m. Live music, art and plant activities, garden games, photo ops, plus coffee and teas and more. Again, check out www.alaskabg.org (and join).
ABG Plant sale kickoff Saturday, May 10, 10 a.m.-4 p.m. Guess what? Members get to shop early, starting at 9 a.m. If you were a member you would know that. What are you waiting for?
Wildflower workshop: Oh, it’s full. Members beat you. See what I mean?
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