OK, so for the past 2 or 3 weeks, the days have steadily gotten warmer and warmer, with nice warm sun. However, this week the weather has turned back to winter. In fact, a few nights this week they are predicting frost, or even a "hard freeze". My question is, now that all my plants have started to leaf out, do I move these small plants (1-2G) into my unheated garage for a few nights? How do frosts affect new leaves? Normally I wouldn't worry, but if there truly is a "hard freeze", I wonder if some of the soft new leaves could be damaged. Thanks!
The experience of Dutch growers, where spring frosts are common, is that Japanese maples can take -2/-3°C for short periods (a couple of hours during the night) without major damage to the new growth. Otherwise protection is required. Gomero
We also get spring frosts often in the UK, and my experience is similar in that the temps are usually only a couple of degrees below zero and it doesn't damage the Japanese maples. To be honest I tend to ignore the frosts and let the plants get on with it. Obviously it depends how soft the new growth is. One thing I do do, is never fertilize till after the danger of frost has passed. Also, I try to make sure my plants will not be in a position where strong direct sun will shine on them while frost is still on the leaves and shoots in the early morning. Not sure of the scientific basis for this, but it seems the only spring damage I have ever received is plants in this type of exposure.
Thanks guys! I'll just monitor the situation, but it looks like unless something really freaky happens, maybe I'll let them be. (Well maybe not the smallest 1-gallons...) Edit: But if they die, I blame you personally!!! (Just kidding haha!)
Actually watering is the best defense against frost, if its just for a night or two. It prevents the formation of the frost crystals, which damage the cells. Some of the orchards here actually turn on the sprinklers and let them run at night when a frost is predicted. Ice may form on the fruit, but it does no damage. Frost WILL do damage. It is also the primary mechanism for pseudomonus infections to enter the plant. In fact, psuedomonus is enitrely dependant on frost. No frost - no pseudomonus! If your plants have significant leaf-out you may think about taking measures. If the buds are just breaking, most have little hairs that protect them in the early stages of growth.
I would bring them into the unheated area if possible. My understanding is that the watering method will help against frost, as K4 mentioned. However, if a hard freeze occurs (as I believe you are worried about), then the watering can actually backfire. At the least, bring in the more cherished/fragile to avoid the worry and/or potential guilt. We had a similar situation here, where we had early leaf out and then the temps that touched 31 F two nights running. I didn't bring mine in and most were fine. But one stalled and my heart has been in my throat ever since. If I could go back in time, I would bring it in just to avoid the anxiety.
We lost a lot of plants this year, We lost them because we grew them a little to well, and with the weather we had this last winter, the plants could not handle the cold. their bark turned soft and lost color. I am not worried because we were overstocked any ways
In Philly we get frost right up until May. Right now, the last day of March, about 1/2 my trees are partially leafed out. I've never considered taking any frost precaution. We've had an inch or two of snow, on just leafed out trees, without noting any problems. Doesn't it seem improbable that temperate trees would suffer from Spring frost? In places prone to precipitous drops into the low 20's (08) it would obviously be destructive. A frosty dip just below 32 seems to me an ordinary Spring event. This pic 3/31/10.
That was my reasoning behind leaving all my trees out in their spots. But then I started to worry about my littlest tree, a 2 year graft of Olsen's Frosted Strawberry because it looked like it may have stalled. In the last 24 hours I've seen the leaves start to perk up. So it was perfectly fine where it was in its roomy and heavy glazed ceramic pot. I, on the other hand, was not fine. I fretted about that tree every day multiple times a day for the last ten days. In hindsight, I would bring it into a protected location, not to spare the tree, but to spare myself the anxiety!
