Why rain gauges break and plants heave

– Posted in: FAQ, Weather
9 comments

It was a balmy 57F out today, a pleasant change from last week’s snow, so I took a stroll around the garden to see what I could see. I saw the new growth of sedums at soil level, and I saw colchicums emerging from the earth, way too early as usual.

Not all colchicums send up their foliage in early winter, but the kinds that do wind up with browned tips by the time spring actually arrives.

Not all colchicums send up their foliage in early winter, but the kinds that do wind up with browned tips by the time spring actually arrives.

I also saw the damage that freezing water causes:
Every year I think I'm going to remember to bring in the rain gauge, and every year I don't. That's why I buy inexpensive rain gauges.

Every year I think I'm going to remember to bring in the rain gauge, and every year I don't. That's why I buy inexpensive rain gauges.

Water expands as it freezes

You were taught this in grade school: water expands as it freezes. You were probably even told that water gets into the cracks of rocks, and actually breaks the rock apart when it freezes. Unless you actually saw this happen, it probably seemed no more than another fairy tale that grownups told, right up there with Santa Claus.

I’m here to tell you: ice happens, and the consequences can be anything from annoying to deadly. It is annoying when the rain gauge you bought at a discount store breaks from the force of the undrained rainwater expanding as it freezes. It happened last year, too. Until I get a fancy self-emptying rain gauge, I will be buying the least expensive rain gauge I can find that measures in tenths of an inch, because I am always thinking I can wait until it gets warmer before emptying the gauge, and then I forget. The force of the expanding ice was enough to break the plastic bracket as well as crack the glass:

Ice happens, and it is a force to be reckoned with. It snapped the plastic bracket as it expanded.

Ice happens, and it is a force to be reckoned with. It snapped the plastic bracket as it expanded.

Heaving kills plants

When that same moisture is in the soil and then freezes, the results can be deadly for garden plants, especially newly planted ones. The water in the soil expands and pushes the plant up. When that ice melts, the soil level goes back down, leaving the plant’s roots exposed to the drying air. Cold climate gardeners call this heaving.

Heaving is more common during mud season, that transition time between winter and spring when the soil is subjected to freezing and thawing, but in a weird winter like we’ve been having, it can happen any time snow cover is lost. I was looking for heaved plants as part of my mild weather stroll, but didn’t see any. Any fall-planted perennial, tree, or shrub is at risk (we don’t plant annuals in the fall, silly), but heucheras and primroses seem vulnerable no matter how long they’ve been in the ground. The solution is to discover the plants before the roots have dried, and push them back down into the moist garden soil. Then cross your fingers.

You mild weather gardeners getting a taste of Ol’ Man Winter this year, consider yourself warned. The ice that’s in the ground is just as deadly as the cold air above the ground.rain_gauge_broken

About the Author

Kathy Purdy is a colchicum evangelist, converting unsuspecting gardeners into colchicophiles. She would be delighted to speak to your group about colchicums or other gardening topics. Kathy’s been writing since 4th grade, gardening since high school, and blogging since 2002.

What differentiates a bulb from a perennial plant is that the nourishment for the flower is stored within the bulb itself.…There is something miraculous about the way that a little grenade of dried up tissue can explode into a complete flower.

~Monty Don in The Complete Gardener pp. 142

Comments on this entry are closed.

jeff-nhn December 30, 2008, 4:49 pm

I don’t believe rain gauges are the issue here. I believe it is the up and down temperatures we experience almost every year now. I also looked for heaving plants and was unable to find any. I’m hoping our temperatures get back to normal. Normal temperatures (even when cold) are much better than these bitterly cold days followed by warmer than normal days that are 20 – 40 degrees above normal.

debra December 29, 2008, 10:44 pm

hey there Kathy. In my experience, Heucheras have a tendency to heave everywhere, freeze or not! What’s up with those plants? Do they have higher aspirations than other perennials?
Can you believe we have had frost on the windshields every morning this week, here in Zone 10? I think it was warmer in CCG land than SoCal this week! Brrr.
Enjoy the sunshine, and your promise of spring,
xoxo deb

Susy December 29, 2008, 6:41 pm

I only every bought one rain gauge and that’s what happened to it. I’ll have to get another one soon though.

Mr. McGregor's Daughter December 29, 2008, 10:50 am

Another good reason to invest in one of those self-draining gauges. I already was thinking about 1 because I don’t like the idea of standing water in the summer (hello, mosquitoes!). Mulching Heucheras is a tricky thing. Too much & you kill them, not enough & they heave themselves out. Why can’t it just stay below 32 degrees all winter?

commonweeder December 29, 2008, 9:59 am

The durability of rain gauges is a real problem. Ours was destroyed by a freak and violent hail storm. I haven’t gotten around to replacing it, but I think your idea of getting inexpensive ones – easily replaced – is a good one.

eliz December 28, 2008, 9:46 pm

Yes, heuchera heave, the bane of my existence. Oh and also the death of all expensive heucheras that are more interesting-looking than Palace Purple.

dlyn December 28, 2008, 6:36 pm

Weren’t we just talking about broken rain guages a couple weeks ago? I actually retrived mine in time this year. We still have good snow cover out here, but it won’t last if this warm weather keeps up. Great post Kathy!

Ann Travers December 28, 2008, 6:03 pm

Hi Kathy.
Great post here. Very informative and I’ll keep a close eye on the primroses my father gave me this summer when they moved from their home to a retirement community. Thanks!
Ann