Sowing success a matter of temperature

In an annual ritual of spring, gardeners emerge from their houses in mid-March, blinking in the thin sunlight as they peer around the landscape, assessing what needs pruning, cleaning, or mending.  All it takes to get our sap rising is for the month to turn to March, and we shrug off our winter lethargy in favor of planting the garden.

 That harbinger of spring acts like a jolt of electricity on our minds, sending a surge of energy urging us to get our hands in the soil and sow seeds.  But if you’re too quick to cave in to eagerness, you might find that your good intentions are not appreciated by the seeds you lovingly pop into the ground.  They’re not impressed by the calendar; they could care less about leprechaun and daylight savings.

 What the seeds want is warmth.  To ensure seeds sprout instead of sulk, gardeners need to plan on two things: frost date and soil temperatures.  Average date of last frost is what most rely upon to plan their plantings; it’s calculated from 30 to 40 years of data.  In Boulder the probability of frost is 50-50 on May 3, in Loveland May 4, and Longmont May 5. 

 Because it’s still possible to get frost after these dates, many gardeners prefer to use the 10-percent probability of frost date as their benchmark, which in Boulder is May 13, Loveland May 16, and Longmont May 17.  You still need to plan for protection from the odd cold snap, but the likelihood of frost is much less when waiting until mid-month.

 Yet there is a second temperature factor that Colorado gardeners shouldn’t ignore: soil.  Chilly soils will limit germination of seeds, and if the ground is both wet and cold, seeds will rot instead of sprouting. 

 Early spring vegetables vary in required soil temperatures.  Spinach and lettuce are the most tolerant, needing soil to be 35-degrees to germinate and 45-degrees or warmer to grow well.  Peas, chard, onions, mache, and parsley can grow in soils at 40-degrees, but do best in soils of 50-degrees or warmer.  Soil temperatures of 60 degrees or warmer are perfect for fava beans, beets, carrots, and leeks, while scallions, Asian greens, kale and kohlrabi like is slightly warmer, at 65-degrees.

  Can these plants germinate in slightly cooler soils?  Yes, but for them to grow rapidly and thrive – key to sweet flavor and tenderness – gardeners should pay close attention to bringing soil temperatures up.

 To do this, plastic mulches or water-filled walls are helpful.  If you’re choosing to go with warming by plastic, clear plastic works better than black at warming soil, bringing the temperature up 10 to 15 degrees in a few days. Make sure you weight down all edges of the plastic to keep it from blowing in the wind, and lay it out so that it touches the soil a week ahead of planting to give your seeds a warm start. 

 Punch holes into the plastic to sow seed if you plan on leaving the plastic in place over the season.  If you are removing the plastic once temperatures are stable, laying the sheets down in strips that can be folded back for planting space is a good way to leave the plastic between rows for a few weeks.  If using water-filled walls, place them out one week before planting to help warm the soil.

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Jealousy is such an ugly state

Earlier this season I posted a story of Jim Koski, the 74-year old gardener in Lockport, Illinois.  Jim, through a method of early seed starting, salt paper wraps and soil warming, settled his plants in the ground a full month before we would ever dream of doing so. 

With harvest underway, let’s take a quick peek at how Jim’s doing:

Dear heavens it looks like those plants are big enough to eat Jim alive!  With nine-foot-tall beans and eight-foot-tall tomatoes, Jim is setting the bar high for gardeners across the USA.  Rumor has it the peppers are the size of Buicks.  A typical day’s harvest is 10 tomatoes, something I can only achieve in my dreams. 

Yes, it helps to have rain, and Illinois has had its share this year.  One recent storm dumped seven inches in one day on the Chicago area.  I’m lucky to get seven drops at my house.  And true, Jim has what we like to call soil – rich, crumbly, and home to the flora and fauna that makes roots happy.  At my place, the soil is what experts describe as “adobe brick”.  But what really makes the difference for Jim is fish fertilizer which, given the amount of rain, might help those plants sprout gills and swim away. 

I’m impressed, and a tad jealous of the super-sized garden.  I think I’ll go home and give my plants a good pep talk. Good job, Jim!

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First vegetable garden; a gardener’s confession

True confession time:  when I started my first vegetable garden, it frightened me.  Yes, I felt good growing and tending; I read all the magazines I could for advice.  But when the time came to harvest the first peppers I’d ever grown, I faltered, afraid to eat them. 

 

I was young, inexperienced, and did the only thing I could think of to see if it was safe:  I fed it to my spouse.  No, I don’t have a desire to see him expire.  But he can eat darn near anything; he’s practically a goat.  So I served him and waited, and once it was clear he wasn’t clutching his stomach and keeling over, I figured my first harvest was a success.

 

Since then I’ve become addicted to vegetable gardening, so much so it’s an obsession.  But I won’t seek therapy because I have plenty of company in this madness; chances are any therapist I’d see would pull out photos of their garden and offer to swap seeds.

 

Despite the anxiety of that first garden the season was magical, and if you’re ready to try growing your own, start off right and relax.  The food you’ll grow will taste better and be more nutritious, but keep a spouse or friend around, just in case.

 

Look around your yard and choose a site that gets eight hours of sunlight or more per day.  If the area was lawn, you’ll need to cut the grass, root and all, from the ground.  Sod cutters are excellent for this, but if you don’t have one, a shovel will do.

 

Dig or till the area, adding in compost or aged manure (see previous post) spread six to eight inches thick along the surface.  Vegetable roots grow deep; you’ll need to dig down at least 12 inches.  After that, go pass out on the couch, waiting a week for your body to stop screaming that it’s the Armageddon.

 

Once you can move again, lay out soaker hoses along the rows you plan to plant.  Soaker hoses keep the water where the plants need it – on the soil.  Sprinklers waste water by evaporation and soak leaves, spreading disease.

 

Then plant – now is the right time to pop in peas, lettuce, spinach, onions, leeks, radishes, beets, or other cool season crops.

 

 

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