Cold Damage on Winter Crops

garden dec 9 2014

Well  here it is in early December and not surprisingly, most of the outside crops in the main garden, ‘bit the dust’ as they say—died. A few are still alive. It is warmer now—here are the results of those cold snaps we had.

 

The Toscano Kale with freeze burn. It is more sensitive to cold temperatures  than other kales

Toscano Kale

The Toscana (aka Lacinato or dinosaur) kale got severely damaged. It is cold sensitive and although it’s not completely dead, it is unharvestable. Here it is with the leaves burned from the cold.

 

Russian Red kale is still alive

Russian Red kale

 

The Russian Red and Curly Leaf kale are still going and have some damage as well but the new growth is doing well. I haven’t watered them at all-nature has with a little snow and a nice rain the other day- almost an inch. I do have them covered with 2 layers of winter weight row cover.

gourds in field

The gourds are still drying in the field. Some are starting to get lighter in weight so I will put those in the garden shed to finish drying. The rest will stay outside until they dry more.

bubble wrap down on windowsThe green house is button up fairly tight now with just a little venting at the top panels. I’ve put the bubble wrap on all the windows (bubbles faced to the window) for extra insulation. I’ve also put the 4 barrels with water in them on the north wall for them to absorb heat in the daytime (I took them out during the summer), releasing the heat at night (the theory is that the sun which is lower and further to the south will hit them on the north wall and warm up in the daytime). I’m not sure I have enough barrels to do much good but even one degree will be helpful once it gets cold again.

winter lettuces

I’ve planted 2 winter lettuce varieties in the green house as transplants back in early November. The cold hard varieties are a green variety-Winter Wunder and a red variety-Marshall Red Romaine. They both have made it so far through those cold snaps although they have slowed down in growth because of the shorter daylight hours. They will stop growing until sometime in January when the daylight hours start to get longer.  Winter Wunder is my favorite lettuce but only grows well during the cold months. When it starts to get even a little warm, it will bolt. The lettuces have 2 layers of row cover over them at night and have some protection from the unheated greenhouse (at least from the winds). I’ve also noticed that the lettuces don’t need a lot of water now (about once every 2 weeks). It will be interesting to see if they make it Dec-February. Don’t they look wonderful in the winter!

There has been about a 4-7°F difference between the greenhouse temperature and the outside temperature at 7 am in the morning when I check everything. When I add the row cover at night I get about 4-6 degrees more protection. I’m not sure what to expect this winter since this is my first December-January  in the greenhouse. Last year when we finished up the greenhouse I start planting on February 17th so now I will see if these established greens can survive Dec-Jan.

USDA Plant Hardiness Zones and ‘average first frost free dates’ explained

NMSo what are USDA Plant Hardiness Zones? And what is this ‘first frost free date’ we hear about as gardeners so often?

The Plant Hardiness Zone is a standard set by the USDA (United States Department of Agriculture) and is calculated by accumulating many years of data. Zones are used by gardeners to help determine which plants will most likely thrive in their area. “The maps are based on the average annual minimum winter temperature, divided into 10 degree-F Zones”. There are 13 Zones, the coldest being Zone 1 and the warmest is Zone 13.

In Santa Fe, we used to be in USDA Plant Hardiness Zone 5 but now Santa Fe is in Zone 6b (-5 to 0°F). The reason our Zone has been changed according to the USDA is because it has better models to follow with more information gathered throughout the years- not necessarily because it’s getting warmer (although I do believe that too). Some areas in our county could be Zone 6a (-10 to -5°F) if they are closer to the mountainous areas. If you are not sure what zone you live in (where ever you live) go to the USDA plant hardiness site and type in your zip code and it will tell you what zone you are in-it’s as simple as that. So when you go to a nursery and the plant tag says zone 7-forget about it—it won’t survive our winters but any tag with Zone 6 or lower number should survive.

The average first frost free date is the date that we can safely put plants outside in our gardens. Notice I said average because some years we are colder and some years warmer. You’ll just have to watch the weather closely in spring for deciding if you want to try to sneak them out earlier in your area if spring appears to be a warm one. In Santa Fe our first average frost free date is May 15. So plant away outside after May 15, unless you hear we are getting a hard freeze! Of course if you are starting them in a hoophouse or greenhouse, you can start seedlings much earlier.

Now, once you know your planting zone and first frost free date, you can use the many tools available on the web for calculating all kinds of things from seed starting to succession planting to harvest times. Many seed companies have web tools to help you calculate the dates. In my next post I will show one such tool I use.