Spring gardening tips from a horticultural meteorologist...
What a wacky weather month this has been! Temperatures are running 11 degrees above normal and don’t look appreciably cooler for the next week and a half, at least. But, compared to the Midwest and Great Lakes, we are underachievers!
Our unseasonably warm readings have pushed soil temperatures in much of the area into the 50s; warm enough to plant both seeds and seedlings. At the rate we are going, my pansies and cabbages are going to succumb to the heat before you know it.
That’s probably an overstatement but it does worry me when readings start inching into the 80s so soon. The best thing I can do is a little sprinkling in the afternoon to thwart the heat on my cool weather loving plants.
Given this warmth, do we dare to start planting seeds and seedlings of tender plants outside?
I am a daredevil myself and probably will start planting some seeds that will germinate in about a week to 10 days. So what is my risk of getting burned or, should I say, frozen? One of my favorite web sites - Davesgarden.com (no relation to me) features a handy guide on the odds of a frost at a certain date.
I put in my zip code and, voila, it returns the closest matches. For my zip, it returns one for D.C, on the west side of town (Dale Carlia Reservoir), that will suffice. Assuming I plant this weekend and expect emergence 10 days later, my plants would be vulnerable to frost through around April 2. The table the website supplies indicates there is an 80% chance of a 32 F reading after April 2 but only a 50% chance of 28 F - doomsday for these plants.
Given the way things have gone this season and my risk tolerance, I intend to plant nasturtium seeds this weekend but probably not chili peppers, yet. You can look at the table supplied at Davesgarden.com, determine your own comfort level, and plan(t) accordingly.
One more thing to note about our abnormal weather: moisture is quickly becoming a scarcity. We have only seen about 65% of normal rainfall since the beginning of the year. That is only a deficit of 2.5” at Washington National but there are additional factors to consider this season that should motivate you to find your hose:
1) There has been no snowmelt to boost soil moisture this spring in most of the area.
2) Unseasonably high evaporation rates resulting from plants putting on new foliage and the drawdown in the limited soil moisture reserves
There is hope on the horizon in the moisture department, as recent model runs have been giving us the chance to eat into our deficit this weekend. The big storm out in the middle of country heads right over us. Keep your fingers crossed!
I am sad to see the accelerated bloom cycle, but at least we get some snow. That is, a blizzard of cherry and magnolia blooms carpeting the area! Many of the early blooming bulbs are already fading away but that only means that there is a whole host of new blooms to see.
Late blooming daffodils are a sight to behold at the National Arboretum if you get a chance go. I have already seen some of the early azaleas starting to bloom in the city - it makes my head spin.
Are you seeing any crazy early blooming already? Let’s hear about it.
I hope you have had time to get out in your garden and enjoy this special and comfortable time of year. I managed to put down over 5 tons of compost, my plants are happy but my back isn’t. I’ll have more on that next time.
Capital Weather Gang meteorologist David Streit is also an active gardener. He earned a certificate in landscape design from the USDA Graduate School and volunteered many years at the National Arboretum.