Archives for posts with tag: freeze protection

We were under a Frost Advisory last night. That’s the warmest of the cold-weather cautionary notices issued by the National Weather Service. It indicates that temperatures may drop into the range of 36 to 33 degrees over the duration of the advisory.

Was there any real threat? No. The overnight low forecast for our area was in the upper 30s, at the upper end of the advisory scale. Frost was possible, especially at daybreak, but not very likely to occur.

Did I cover the garden anyway? Yes. Even as the likelihood of frost or freezing temperatures diminishes, the consequences of their occurrence increases. The farther along the vegetables are, the more exposed they are to damage. Also, the later in the growing season that damage occurs, the larger the investment (of time, energy, materials) that is lost.

It’s a good example of risk analysis. Moderate likelihood multiplied by high consequences produces moderate risk which can be mitigated with low cost (throwing plastic sheeting over the planters is easy, provided I get the warning in time). Overall, the risk to the garden is low.

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The temperature did drop into the 30s overnight but there was no frost this morning nor signs that anything froze. It has gotten very easy to throw the plastic tarp over the planters so “better safe than sorry” is my philosophy.

Timing remains critical, however. I must wait until the sun has set (or is about to set) before placing the black plastic sheeting over the planter and in the morning, I need to get outside early and remove it before the sun’s rays fall directly onto the garden. Otherwise, the planter would become a solar oven and in no time, we would have roasted beets and carrots.

We’re leaving on a road trip tomorrow which motivated me to do more potting up this afternoon. The basil was ready to go—the seedlings are about three inches in height—but the other herbs are coming along much more slowly. The rosemary is growing at a particularly leisurely pace. Despite three months under the lights and over a heating pad, the seedlings are still mere wisps with only a few leaves each. I potted them up anyway, along with the sage, oregano, thyme and spearmint.

I also moved the eggplant and red bell peppers into pots. Like the planting before it, the second try at orange bell peppers yielded no seedlings. Clearly, this lot of seeds has lost its viability—and much sooner than expected. In general, the germination rates of last year’s seeds are very low, leading me to conclude that saving seeds is probably not worthwhile after all.

To wrap up the potting, I transplanted the second batch of lettuce heads into another pair of window boxes. This presented me with a storage problem because although I can fit two drainage trays onto each shelf of the seed-starting apparatus, there isn’t enough room in a tray for two of these larger planters.

So I ditched the trays and doubled up on the window boxes. The boxes that contain the soil and lettuce have their drainage plugs removed while the boxes into which they are nested do not. The lower boxes act as water catchment devices without taking up much more space than single planters. And even better, four of the compact units fit crosswise on a shelf. I may have figured out how to have fresh lettuce year ‘round.

You can tell that we’ve finally passed the point at which cold nights can be expected; there is a freeze watch in effect for tonight. I’m not too worried—the National Weather Service does not actually predict sub-freezing temperatures—but I will cover the east planter with black plastic sheeting just to be safe.

The radishes, always first off the starting block, made their appearance three days ago and the Sugar Snap peas, not to be left behind, started to peek out from the soil a day later. There are now seedlings to protect and the root vegetables are particularly susceptible.

With the trellis in place, I cannot fully cover the peas, but I don’t think it is necessary. The pea shoots are quite hardy and even without completely enclosing the planter, the sheeting will capture the heat that the garden acquired during the day.

I wonder what date the National Weather Service uses for last frost in our area? I conservatively use May 5, which has a 90 percent confidence level (i.e., there is only a 10 percent chance that the temperature will fall below freezing). Apparently, the NWS uses an earlier date.

I suspect that they use a lower confidence level, probably at a 50 percent chance of exceedance. Their date—whatever it might be—is less conservative from a freezing temperatures point of view but more conservative from a freeze warning point of view (i.e., its use will likely generate more warnings). Given that the NWS is in the business of forecasting the weather and not gardening, this makes perfect sense.

Mother Nature continues to be a bit confused about what season it is.

After a glorious weekend when temperatures reached through the 70s and into the 80s, we awoke this morning to a one-inch-thick layer of snow and ice which fell overnight.

Like the winter storms before it, the snowfall cloaked the still-leafless trees in a shroud of white. It has been long enough since the last one that I can again appreciate the beauty.

Sadly, however, I could not escape the need to sweep the walk and scrape the cars, tasks made more difficult by the persistent cold temperatures. That I do not appreciate. Nonetheless, it is forecast that the day will warm to above freezing and the snow should soon melt.

The planters are also blanketed by snow but I’m not worried about the seeds we planted on Sunday (see April 13, 2014). Probably nothing much has happened beneath the soil’s surface. The seeds will pause whatever they were doing and will resume when the soil heats up again. In effect, it will be as if the seeds were planted today.

Well, according to the seed sowing calendar, gardening tradition and conventional wisdom, St. Patrick’s Day is the time to sow the first seeds outdoors.  And not just any seeds:  today is the day to plant peas.

I fully embrace this idea.  It encourages a return to the outdoor garden.  It emphasizes the idea of rebirth and reawakening that is consistent with spring at its most conceptual.  And it involves (for us) sugar snap peas, one of my favorite vegetables, both to grow and to eat.  As an added bonus, it turns out that early sowing during the cusp season between the deep of winter and the peak of spring is actually good for the plants.

Cold weather (and it is usually cold in March) means that the pea shoots will grow slowly.  The restrained growth combined with the accompanying stress results in stronger leaves and stems (although too much stress is problematic; like any other plant, peas must be protected from freezing).  When planted in warm weather, peas can grow too quickly and weakly.  Worse, the period during which the peas are sweetest—fleeting at best—is even shorter.

Sadly, for the second year in a row, conditions will not allow us to sow any seeds outdoors today.  The garden beds, although again fully visible (see February 14, 2014 for a photo of when they were not), are still surrounded by a deep layer of snow.  The soil surface is overlain by a thick blanket of ice.  Preparing the garden in spring might involve turning soil but it should not include shoveling snow.

So, nothing going on outside.

What about inside?  All of the herbs have sprouted (the new seeds yielded seedlings about a week ago).  The second round of lettuce seeds have also started to germinate while the gangly lettuce seedlings from a month ago are almost ready to pot up (the taller ones were pushing up on the cover of their tray so I removed it).  The eggplant and bell peppers, seeded last week, should pop up any day now.

It’s more than enough to keep me going until the weather warms up.

Providing freeze protection is annoying.  The plastic sheeting must be supported above the seedlings (so as not to crush them) but it must also be weighted down to prevent it from flying off in a gust of wind.  Furthermore, it cannot be put into place until the sun is low in the sky (otherwise, the plants would cook) and needs to be removed shortly after sunrise (for the same reason).  Ironically, the early morning hours can be the coldest of the day.

But the freeze protection has its positive side.  There’s the protection against freezing, of course.  As a secondary benefit, however, the plastic sheeting also provides physical protection.  A critter (or critters) romped through the garden last night as occurs several times each season. They rarely damage the plants but with the garden covered, there was absolutely no danger.  The vegetable plants made it through the night untouched.

The beast (or beasts) had some fun with the uncovered east half of the east planter, though.  What a mess!  It isn’t clear what they are looking for.  Gold?  Buried treasure? Buried acorns?  Insects?  Nor is it clear whether they found anything.

Regardless of the intent or success of the overnight raid, the soil and mulch were easily restored.

Once again, the odds are against us.  Last night, the National Weather Service issued a frost advisory and tonight, a freeze warning is in effect.  We are more than a week beyond the official last expected frost date but as noted before, that doesn’t mean that frost or freezing temperatures are impossible, just that they are unlikely.  This late in the season, it should be very unlikely.

Have we entered a period of unlikely occurrences?  If I had a jar filled with uncooked rice and beans, would the two be perfectly separated, one layered over the other?  [See The Eyre Affair, by Jasper Fforde.]  Would now be a good time to travel into deep space?  [See The Hitchhiker’s Guide to the Galaxy, by Douglas Adams.]  Should I run out and buy a Lotto ticket?

Last night, I covered the most delicate seedlings in the garden—the romaine and red leaf lettuces—and tonight I will do the same.  But with a greater risk of freezing temperatures, I will also cover the west planter.  I should be able to get black plastic sheeting over everything except the peas who extend well above the top of the planter (even if their trellis was not in the way).  They will have to tough it out.

Even during the day it is colder outside than it is indoors (just like winter!).  Therefore, I am suspending the hardening off.  It’ll be like a snow day except that everybody has to stay inside.

Late yesterday afternoon, the National Weather Service posted a frost advisory for our area.  I didn’t see this until I checked the forecast at about 9:00 pm.  The advisory did not seem to make sense—the expected overnight temperature was warmer than 40 degrees—but just to be on the safe side, I covered the garden with a sheet of black plastic.  The effects of micro-climate should not be underestimated.

The temperature did drop into the 30s (but only just, at 39 degrees) so there was no real danger of frost.  Still, I imagine that the peas, carrots, turnips, radishes and beets appreciated the protection.  They have spent their entire (if short) lives out in the cold and probably envy their cousins (the tomatoes, squash, cucumbers, eggplant, bell peppers and basil) who have yet to venture outdoors.

Now that we are into the month of May, the risk of further frosty nights is rapidly diminishing.  It’s tempting to think that the threat has vanished but statistics don’t work that way.  No, there is still a non-zero chance of freezing temperatures but the probability has dropped below ten percent.

It’s Election Day!  Finally, an end to the relentless campaigning that has filled every day since the spring (remember the interminable Republican primaries and debates?).  We voted early this morning and even though this is my eleventh presidential election—and who knows how many other state, local and school votes there have been—it never gets less thrilling.

It was very cold over night—temperatures dropped into the low 20s—and we awoke to a frigid and frosty morning.  Now that Halloween has passed, the National Weather Service no longer issues warnings (cold weather can now be expected every night, I guess) but I check the forecast every day and was prepared.  I brought in the last garden hose last night and shut off the faucet from inside the basement.

But I decided not to cover the radishes.  They have not been making much progress and it is unlikely that they would ever reach full maturity, especially the French Breakfast variety whose roots have not even started to enlarge.  Although the leaves were covered with a fine lace of frost, they fared better than I expected.  When the ice melted (by mid-morning), only a few of the leaves had the deflated look typical of cold-weather damage.

Nonetheless, I pulled them all up.  About half of the Pink Beauty radishes were near ripe (if small) but the other half and almost all of the French Breakfast radishes had not developed at all.  This crop is mostly leaves and in keeping with the season, we’ll sauté them (instead of throwing them into a salad).

The forecast held up and the temperature did, in fact, drop below freezing over night.  When I looked this morning—the sun having already risen—the thermometer was reading about 31 degrees.  The Weather Channel reported a low of 27 degrees so it may have been sub-freezing for much of the night.

However long it was, it was long enough.  Almost all of the plants that we left unprotected—the string beans, tomatoes, bell pepper and eggplant—were affected by the cold and subsequent warming; their leaves are hanging limp and lifeless.  Freezing and thawing has also cast a literal pall over the garden:  the greens are tinted with black, as if the garden is now permanently in shadow.

The radishes, toasty-warm beneath their tarp, weathered the frost well.  When I uncovered them, they looked as fresh as on any other morning.  It remains to be seen, however, whether there is enough sun left in the season to develop them to maturity.  At the moment, they are still nothing more than sprouts.

Although left out in the cold, the parsley and other herbs also fared well (they don’t need no stinkin’ tarps).  I was not surprised by this.  Last year, most of the herbs survived the late-October snowstorm that left them covered by a foot of snow.

I appreciate having gotten two day’s warning of the freeze—thank you National Weather Service—and am very glad that we were able to successfully harvest our remaining viable produce before it could be damaged.