The big freeze is past and hopefully will not repeat. Now it is time to plan for the spring Houston vegetable garden. I planted tomato seed under the grow lamp indoors on January 13. They are coming up now. One new variety this year, Early Girl, and the line up from last year: Marglobe, Floramerica, Merced and Celebrity. All of these are determinate tomatoes, which I believe are best for growing in Houston gardens. I still have 2-3 seed of Merced left–unfortunately this good variety for Houston gardens is no longer available. I saw a seed catalogue that recommended Danson Tomato 435 as a replacement, but I have not tried it. I planted some Sweet Chelsea to give to my brother and I may plant one myself. I am leaving early this year for Montana and Sweet Chelsea just takes over the place.
I also planted some Packman broccoli under the lamp. I normally raise broccoli in the fall but will try in the late winter/spring this year, because I am not going to plant corn since I won’t be here to pick it. I also planted some super sugar snaps under the lamp to supplement the poor stand I got from direct planting. The weather the last half of December was just too cold for good germination.
A few days have now gone by so that I can assess the situation in my Houston vegetable garden. I recorded the following low temperatures:
Friday: 27
Saturday: 24.5
Sunday 28
The Friday low was about the same as Hobby, but the Saturday and Sunday (and Monday) temperatures were 3 or 4 degress higher. This pattern is typical. When the wind is blowing strongly, my temps are about the same as the airport, but when conditions are still, the TMC area (and probably most of area the inside 610) temperatures are significantly higher. I think this follows from what I learned years ago in ChE 353–convection will equalize the temperatures, but we get conduction warming and less radiation in the areas around big buildings.
The vegetables basically had no freeze damage. A couple of fronds on the fennel are bend over, but the plants are going to be ok. Some tips on the mustard and lettuce are “burned” a little. I could see no real difference between what was covered and uncovered. The young lettuce I covered with bubble wrap was perhaps helped a bit because it could hold the ground warmth. Otherwise I think the temperature was the same on both sides of the covering, again following ChE 353.
The Mexican lime tree status is still undetermined. I wrapped it with freeze cloth and put a light under it. It will lose most of its leaves but I am hopeful that the stems are mostly ok.
Bottom line: Covering is good for protecting against frost but not so good in protecting against a freeze unless the plants are very small and therefore close to the ground.
Global warming, where are you? It has been the coolest winter for the Houston vegetable garden all season and now it is on the verge of being the coldest as well. Here in the Medical Center area, the outlook is for lows of about 25. Most winter vegetables and citrus can survive this temperature, but it would be wise to take some precautions. The low 20s are really the boundary between cold and very cold, or survival and freeze death. If things aren’t bad enough, we have the annual Urban Harvest fruit tree sale this Saturday at Rice Stadium. We are scrambling!
It has been so long since I have dealt with a hard freeze, I have forgotten the level of cold hardiness of the various vegetables. Some quick research, including even Bob Randall’s book, has not helped very much. Here are my thoughts and plan:
Lettuce: The leaves will get burnt and ruined; the plant will probably survive. Pick all the leaves and cover the plants if you can.
Fennel: I started raising it after last big freeze–no experience. Plan to havest a couple of young plants and hope for the best.
Carrots: Should be ok
Beets: Likewise do nothing
Cilantro/Parsley/Chervil: do nothing
Sugar snaps: Will cover with frost cloth, but probably ok uncovered. Plants are very small still.
Mustard/Collard Greens: will pick and may cover. Collards should be ok; not sure about Osaka Purple Mustard
Onions: no problem
Arugula: not sure; will cover some with pots and leave others uncovered as an experiment since I have too much anyway
Turnips: think they would be ok but they are ready to pick. Will leave one or two as a test.
Bok Choi: no experience but I have a lot of it. All of it needs to be picked anyhow. Will pick and give away. Leave one for a test.
Citrus: Most should be ok, but I will wrap the bud union on all and throw a blanket over a small satsuma planted last year. The Mexican lime is in real trouble. I had it in a pot but got tired of fooling with it and planted it outside. It grew like a weed last year and got nipped by the early December storm. I put frost cloth over it, wrapped the base with a blanket and put a light bulb near the base. I doubt that it will be enough, but maybe it will not be killed it to the roots.
Stay tuned for a report next week after thawing!