Shop Products
Houzz Logo Print
okiedawn1

Starting/Planting Cool Season Crops

Okiedawn OK Zone 7
15 years ago

Since the planting of cool-season crops can begin soon, I thought I'd post planting dates and notes for the most common cool-season vegetables.

With some vegetables, you get better results if you start with transplants while others, most notably carrots, are very hard to start from transplants and do better when sowed directly into the garden. Some will grow equally well from transplants or from a direct sowing, with the main difference being that transplants usually give you an earlier harvest.

On the dates, I'm using OSU's recommended planting dates, so the first date given is for the southernmost regions of the state and the last date given is for the northernmost regions of the state. Usually, though, I have good crops even when I plant using the last date instead of the first one.

Keep in mind that even though these are cool-season crops, some of them can and will freeze at temperatures in and below the 20s. You can prevent that by covering them with floating row covers, sheets or blankets if a cold spell threatens.

ASPARAGUS: Plant from crowns in spring or fall. Crowns usually start appearing in the stores in January-February. You also can start from seed, but it will take another year or two to get plants to a harvestable size.

BEET: Plant March 1-31. Plant from seed once soil temperature is consistently staying above 45 degrees.

BROCCOLI: Plant from transplants March 1-31. You can plant from seed and, if you do, wait until soil temperatures are consistently staying at 50 degrees or higher. In cool ground, broccoli seed can take 2 weeks to germinate, so the reason transplants are preferred is that the plants are more likely to produce a crop before it gets too hot. The further south you are in Oklahoma, the more of an issue you'll have with early heat.

BRUSSELS SPROUTS: Although technically a cool-season crop, these do better in our climate in the fall than in the spring. In an ideal situation, your brussels sprouts will mature while air temperatures are in the 55-65 degree range. Only occasionally will late winter/spring-planted brussels sprouts be able to form sprouts before the heat arrives. If you want to grow them in the spring, use the planting info for broccoli but don't be surprised if May gets too hot and you get plants that produce nothing.

CABBAGE: Plant from transplants between Feb. 15 and March 10th. Transplants work better than direct seeding because our cool season ends relatively early and the cabbage needs to mature before the weather is too hot. Ideally your cabbage will mature while daytime highs remain in the 60s, although you can sometimes get a good crop even when the highs push up into the 80s. And, you can't plant too early, because young cabbage plants exposed to 40 degrees or lower for a week or two will often bolt and fail to form heads.

CARROTS: Plant from seed Feb 15-Mar. 10. The reason you plant so early is that carrots need to mature before our daytime highs start exceeding the mid-80s. Carrots grow best when temperatures are in the 40-85 degree range. They can be hard to direct sow--surface sow and keep moist for best germination.

You CAN start carrot seeds inside, but it is very hard. One way to do it is to use the cardboard rolls that toilet paper and paper towels (cut those tubes in half) come on. Line up the cardboard tubes in a flat or plastic storage container, fill with a good soilless mix, wet it down, surface sow the seed and keep in a cool location. The carrots will sprout fairly quickly indoors. When you transplant, plant the tube and all in the soil. You want to plant fairly early, before the roots begin to grow out of the bottom of the tubes (which can occur within a week of the seeds sprouting).

You also can make your own carrot seed tapes and plant the tapes. This makes the proper spacing of the carrots easy to maintain.

CAULIFLOWER: Plant from transplants between Feb. 15-Mar 10. Cauliflower is less cold hardy than broccoli, cabbage and kale and does best in mild temperatures that are neither too cold or too hot. If you plant a fast-maturing hybrid, you ought to be able to get a good crop of cauliflower about 2 months after you set your transplants into the ground.

COLLARDS, KALE, MUSTARD & MOST OTHER GREENS: Plant from seed between Feb. 15-Mar. 10. These grow best in moderate temperatures in the 40 or 45 to 70 or 75 degree range. And, yes, you can start from transplants, but often transplants never develop as extensive of a root system as the direct-seeded ones do. Some of these greens, like Mustard greens, develop a "hot" or "bitter" flavor when exposed to daytime highs over 70. Many greens can be harvested 30-50 days after planting.

CHARD (aka SWISS CHARD): Plant from seeds or transplants between Feb. 15-Mar. 10. Unlike many other leafy greens, swiss chard will continue to grow and produce in hotter weather. However, it still does best in cool weather. I've had early plantings freeze to the ground and some will regrow from the roots and some won't.

KOHLRABI: Plant from seed Feb. 15-Mar. 10. This is a little more heat-tolerant than some cool-season crops but still performs best if planted early so it can mature before temperatures start hitting the 70s.

LETTUCE: Plant from seed or transplants between Feb. 15-Mar. 10. You can plant either looseleaf or head lettuce, but often our heat can prevent the head lettuces from making quality heads or even from making heads at all. If you plant the leafy types, you can harvest using the cut and come again method or you can succession sow new follow-on crops every week or two. Once the daytime highs are in the 80s, the quality of the lettuce declines quickly and it is likely to bolt.

ONIONS: Plant from transplants (actual small onion plants) or from sets (small dry bulbs) from Feb. 15-Mar. 10. Be sure to plant only short-day or intermediate-day types because long-day types do not bulb up well here. With transplants, purchase only those that are the same diameter as a No. 2 pencil or smaller since larger transplants are more likely to bolt.

You also can raise your own from seed but it doesn't germinate well until soil temps are in the 50s, and ideally you'd have larger plants from transplants by that time.

GREEN PEAS: Plant from seed (or transplants) from Feb. 15-Mar. 10. In the southermost parts of the state, transplants probably give you a better chance of getting a crop before the daytime highs get too warm. You get the best crop from plants that have bloomed and formed peas before the daytime highs begin exceeding the mid-70s.

IRISH POTATOES: (Note to new veggie gardeners: Sweet potatoes are warm-season crops and will be planted with other warm-season crops in late April to June, depending on where you live.) Plant between Feb. 15-Mar. 10. Plant from pieces of tubers that have 2 to 3 eyes each, or from whole, small seed potatoes. Potatoes will grow and produce best when air temperatures are in the 60-75 or 80 degree range during the day and no lower than the 45-55 degree range at night, so getting them in the ground early is key. You also can pre-sprout these inside to get even more of a head start. If you are planting tuber pieces into very wet soil during a rainy year, dust them with garden sulphur to help keep them from rotting before they sprout.

RADISHES: Plant from seed March 1-Apr 15. Because these can mature very quickly, you may want to succession sow a small patch weekly so you'll have a continual harvest. You really don't want to have a whole packet of radish seed mature at once. You can plant anytime once your soil temperatures are consistently 45 degrees or higher, and you should stop planting early enough that your last succession crop matures before the highs start hitting the low- to mid-80s.

RHUBARB: Plant from crowns as soon as you see them in the stores. The further south you are, the harder it will be to get a rhubarb harvest. Your chances of success with rhubarb improve if you plant the plants where they'll get afternoon shade.

SPINACH: Plant from seed from Feb. 15-Mar. 10. You can plant from transplants but the plants won't grow as well. Spinach needs to be planted as early as possible because daytime highs in the upper 70s and above may cause it to bolt. And, don't fall for advertising copy or articles that say some slow-bolting spinach or lettuce varieties can grow deeply into the summer, because they can't in our part of the country.

TURNIPS/RUTABAGAS: Plant from seed from Feb. 15-Mar. 10. These grow best when daytime highs are in the 55-75 or maybe the 60-80 degree range, so plant as early as you can without subjecting them to temperatures below 20-22 degrees.

HERBS: Many cool-season herbs can be sown in the garden around the time you are planting cool-season veggies. These include chives, onion chives, chamomile, catnip, parsley, and cilantro.

I didn't mention some of the more minor cool-season crops like parsnips, salsify, celeriac or celery because few people grow them these days.

Dawn

Comments (19)

  • river22
    15 years ago
    last modified: 9 years ago

    Thanks Dawn, I've got it clipped and saved in my google notebook.

  • seedmama
    15 years ago
    last modified: 9 years ago

    Dawn, thanks for sharing these dates and adding the commentary. It will be very useful. I am growing celery this year for the first time since 1973. I have great childhood memories of the flavor. Do you have those dates handy? Thanks, Seedmama

  • Okiedawn OK Zone 7
    Original Author
    15 years ago
    last modified: 9 years ago

    River,

    I'm glad the info is useful. I try to post them every year and think I'm doing it a little earlier this year than most years. I was just thinking that if someone wants to order seed and get their seed-starting supplies ready, this thread would be a reminder that planting time is almost here.

    Seedmama,

    You don't really want to grow celery in our climate, do you?

    I have never seen published dates for celery in Oklahoma and there actually is a reason why, and you are not going to like it. There is a reason almost no one grows celery here......

    Celery has very specific growing requirements. One of them is that it must be transplanted in early summer (and, oh, what a problem that is) for a crop to be harvested in the fall. Even after you get the transplants in the ground (and more about them in a minute), it will take you 110 days or more to get mature celery that you can harvest. And, that is assuming you can get the plants enough moisture to survive the summer heat.

    Now, about the transplants. If you buy celery seed (and I assume you'd have to mail order it as I've never seen it on seedracks), and start it indoors, it still will take 3 to 4 months to get your celery plants to a transplantable size. To get your celery seed to germinate, plant the seeds in a flat in a good, sterile soil-less seed-starting mix, and be sure to barely cover them with a very thin layer of soil-less mix. Keep the seeds moist, and they should germinate in about a month. To ensure germination, you'll need to keep the flat at a constant 60 to 70 degrees with nice, moist soil. Covering the flat with a wet burlap bag or keeping it wrapped in plastic wrap helps hold in the moisture. You'll have to grow the seedlings indoors or in a very sheltered outdoor location where the tiny seedlings will not be exposed to temperatures below 45 degrees or above 70 degrees. Once the seedlings are about a month old, you can repot into peat pots, peat pellets or paper cups and grow them on outdoors in a sheltered location. Remember to harden them off gradually.

    Now, about transplanting them into the ground. You have to plant in June in order to get a harvest before the first fall freeze, especially if you are in northern OK. The problem is that celery is a cool-season crop, so planting in June is problematic. Celery grows best in cool temperatures--say, lower than 70 degrees, but will have to grow in thes 80s-100s in order to mature in the fall before temperatures fall to 28 degrees, which will damage or kill the celery. See the problem? Also, celery has to stay wet ALL THE TIME and cannot ever be allowed to dry out. That could be a problem in our summer weather.

    You might be able to work around all the temperature issues if you line your planting bed with heavy 6mm plastic to help hold in the moisture, mist the plants daily (a mister on a timer could do this for you), and errect shade cloth over the plants to allow some sunlight but not full sunlight. Even then, though, the chances of success are quite iffy. For celery to produce a high-quality, edible crop, it needs 4 to 6 months of mild temperatures in the 60 to 70 degree range with only limited bits of temperatures higher or lower than that.

    And, in case you are wondering, most of the celery grown in the USA is either grown during the winter in the lower Rio Grande Valley in Texas (and even then, severe cold snaps often make that iffy) or during the summer in states with a mild summer, like Michigan, Ohio, New York or some of the cooler areas of California.

    If you still want to grow it, let me know and I'll describe a method outlined in one of my veggie growing books.

    And, remember that celery is a biennial, so anything, like excessive cold or heat that interrupts its growth cycle, can shock it into setting seed at the wrong time and ruin your chance of getting a crop.

    I'm not trying to talk you out of growing it....or into growing it.....just trying to explain what it needs and why our climate makes it hard to meet the celery's needs.

    Dawn

  • very_blessed_mom
    15 years ago
    last modified: 9 years ago

    Dawn,

    I too appreciate this post greatly. It does help that you posted a little early so I can get the seed and other supplies ready ahead of time.

    Jill

  • sammy zone 7 Tulsa
    15 years ago
    last modified: 9 years ago

    THis is going to really help me. THanks
    Sammy

  • seedmama
    15 years ago
    last modified: 9 years ago

    Dawn, thanks for the info on celery. It does sound like it's going to be a challenge. I'm going to forge ahead for two reasons. One is I already have the seed and two is sometimes I'm like a preschooler. I do things for the experience instead of for the results.

    When Mom grew it in 1973 it was in one of those tiny foundation flower beds on the north side of the house. The houses were packed close together, so it probably had a lot of shade. Curiously, we were no longer living there and the house was up for sale so the bed got very little attention, including water.

    Based on your info above, I think I'll start it upstairs in a room with large windows on the south and east. I generally keep it in the mid 60's. When it's time to transplant, I'll move it to the area my husband and I call our magic spot. It has a microclimate all its own. It's an L shaped niche about 30 feet on one side and 40 on the other. It faces the southeast and gets great morning sun, filtered midday, and shade in the afternoon. Sounds like it's my best shot, and that's about as complicated as I want to make it.

    I'll approach this project with the reality that odds are stacked against me. But I'll also keep in mind TH from Seminole. He was a fantastic accountant, but it took him many, many times to pass the CPA exam. When co-workers would give him grief about trying again, he would smile and say, "You can't win if you don't enter!"

  • mulberryknob
    15 years ago
    last modified: 9 years ago

    I tried to grow celery here many years ago, despite being told that it wouldn't do here. I'd seen it growing in Washington and California and wanted to try. I ordered the seed, planted in pots inside, transplanted to a raised bed in a shady spot and watered all summer and was thoroughly disappointed. So like Dawn I would say, You don't really want to grow celery in our climate do you? I have grown leaf celery here successfully tho, and picked and frozen the leaves to use later in stews and salads. Dried them too but they lost too much flavor that way.

  • Okiedawn OK Zone 7
    Original Author
    15 years ago
    last modified: 9 years ago

    Jill and Sammy,

    Glad the info is helpful.

    Keep watching because we tend to talk a lot about veggie seed starting and planting in the Jan.-Apr. timeframe. With veggie gardening in our climate, the proper timing of each crop is important in order to get a harvest before the hot weather begins to interfere with or stop production.

    Seedmama,

    I hope you have success with the celery. It is just one of those really, really finicky crops that doesn't like our heat. Under the right conditions and microclimate, I think it could be done here, if only we don't have one of those awful summers that tries to set new records for heat and drought.

    I am headed out the door in a couple of minutes to attend a funeral, but either this evening or tomorrow, I'll describe Jeff Cox's cool celery growing "project". You might find something useful in his method that you can adapt to growing celery here.

    I have toyed with the idea of trying his method, but I know that my drought-plagued area and heavy deer herd/bunny rabbit battles keep me stretched to the limit as it is.

    I try every year to grow rhubarb which, of course, doesn't really do well here. I do it because DH likes the stuff (I can't stand it). Some years we get a good crop, and some years we don't. And, I even do the same thing with certain tomatoes. Growing up in Texas, I had it pounded into my head that the really large-fruiting tomatoes don't grow well here. And, while it is true that they don't grow and produce as well as smaller-fruited ones, I still have to plant a few like Tennessee Britches, German Johnson, and Big Rainbow every year so we'll have a few gigantic tomatoes with superb flavor. Would it be smarter to use the space for smaller-fruiting tomatoes? Of course it would, but I grow a few biggies anyway. So, I know what it is like to buck the conventional wisdom and "go for it" anyway.

    Dawn

  • soonergrandmom
    15 years ago
    last modified: 9 years ago

    The only place that I have lived that celery grew easily was in Alaska. I didn't grow it myself but my friends grew it on their farm in the Matanuska Valley. I was very surprised to see it growing because it was so green. I have become accustomed to the light/white stalks we see in the supermarket. I think that is because they cover it, isn't it? Alaska doesn't have the long growing season, but it is cool and they have exceptional long days during the growing season so that makes up for the length of summer. Cabbage, broccoli, beets, celery, carrots, and potatoes just seem to thrive there. At the state fair the cabbage was huge........50 pounds or so.

  • river22
    15 years ago
    last modified: 9 years ago

    Wow, that is entirely to much trouble to grow celery. I'm going to just buy mine as little of it as I eat.

  • Okiedawn OK Zone 7
    Original Author
    15 years ago
    last modified: 9 years ago

    Carol, I bet it did grow well there in spite of the short growing season. I'm assuming they started their transplants indoors to get them large enough to plant out once the temps were in the appropriate range. And it is the exposure to sunlight that made the celery so green. Most commercially-raised celery is that whitish-green because the celery is blanched. I think the blanching is intended to keep the stalks tender as too much sunlight/heat gives you tougher stalks.

    Seedmama, Here's how Jeff Cox grows celery:

    GROWING CELERY: Several years ago I purchased a book by Jeff Cox called "Jeff Cox's 100 Greatest Garden Ideas". It is a terific book and I love it. One of his ideas is a way to grow celery even if you can't give it the marshy conditions it prefers. If I ever tried to grow celery here, I'd try Jeff's method.

    To start his seeds, he sows them 10 weeks before his last frost. He soaks his seed overnight before sowing them in peat pots and setting them on top of the fridge so the heat can help them sprout, which can take 2 weeks or longer.

    He digs a below-grade trench about a foot wide and 14" deep although he says you can do the same process with a raised bed if you'd rather build up than dig down. If growing in a raised bed, he recommends a minimum height of 6" and cautions anything raised any higher may get too hot for the celery. You still need 14" of depth, but with the 6" tall raised bed, you only have to dig down 8" instead of the whole 14".

    You remove the soil to a depth of 14" for the trench or 8" beneath the eventual raised bed and remove all the soil. Add compost and other organic amendments to create an enriched growing mix that will hold lots of moisure and refill the trench or, for the raised bed, refill the dug-out area and build the 6" tall raised bed above it. By the way, he recommends six celery plants per person.

    If you want, you can add tin cans with the tops and bottoms both removed or pieces of PVC pipe inserted vertically into the ground about to the same depth that your celery is planted, or a couple of inches deeper than that. To water, fill each can or piece of pipe with water and let the pipe carry the water down to the root level of the celery plants. In the illustration in the book, he has one vertical can or PVC pipe in between two celery plants in a sort of checkerboard pattern. (Texas tomato plant growers use this method to water tomatoes, only they use large flower pots or huge, instituitional-sized cans, to water the tomato plants...it is called the Texas Pot method.)

    After you harden off your seedlings, transplant them into the enriched soil which you've pre-moistened so it it nice and damp. He waters his transplants with an organic fertilizer consisting of 1 T. fish emulsion and 2 T. seaweed extract per one gallon of water. Mulch the top of the bed with leaves. As the plans grow keep adding leaves so the stalks are blanched. Blanching celery stalks (but not their topgrowth leaves which need sunlight to grow) helps improve their flavor and keep them tender. This is especially important in a hotter climate where heat stress can cause the stalks to get woody and tough. He recommends feeding monthly and watering as often as needed to keep the bed moist and damp but not soaking wet.

    His recommendation is that you harvest the plants roots and all before frost arrives in the fall. Store them in a box in a cool basement or similar area. If the storage area stays cool enough, celery will store for months. You also could store them in an extra fridge in your garage or laundry room or whatever.

    If you ever run across Jeff's book, it is a wonderful book with projects grouped by the season.

    Dawn

  • seedmama
    15 years ago
    last modified: 9 years ago

    Dawn,
    Thanks for all the information. I'm going to keep my eye out for Jeff's book.
    Here's a little info off the seed packet:
    Celery Tango
    A self-blanching variety with beautiful apple-green, smooth stems with good flavour and texture for that all important celery crunch. Good bolting resistance and stands well during hot weather for reliable crops.

    Of course, just like with spinach, "Good bolting resistance and stands well during hot weather" means something entirely different in Oklahoma than it does in England. But those characteristics, along with my little microclimate may be what nudge me over the top of the steep hill.

    Thanks again,
    Seedmama

  • southerngardenchick
    15 years ago
    last modified: 9 years ago

    Gosh Dawn, GREAT information! I should've come to gardenweb last year... you coulda told me not to plant my mustard greens and cilantro during JULY! LOL...

    Last year was an experiment... this year I'm a LITTLE bit more informed.

    Beth

  • Okiedawn OK Zone 7
    Original Author
    15 years ago
    last modified: 9 years ago

    Hi Beth,

    Life is an experiment....and so is gardening. LOL

    And, stay tuned, girl, 'cause you might be surprised at what you CAN plant in July and August for a fall harvest! Or, at least, you can plant in those months for a fall harvest if SOME rain is falling from the sky. In the middle of a drought, planting in summer for a fall harvest is a lot harder and success is not guaranteed.

    Cilantro is a great early spring crop, though, and you can harvest leaves/stems from the plants themselves to use in cooking during the cool season and then harvest the mature seed which is known as coriander later on after it matures. I wish we could grow cilantro all summer long here, but it doesn't like our heat, as you undoubtedly learned last summer.

    Even after a lifetime of gardening (and more decades than I care to admit to! LOL), I think every garden is still a bit of an experiment because every year (heck, every month) we have different challenges. Sometimes it is late freezes in May, or early hot temperatures in April or May, or stink bugs in July/August (or in May some years) or hungry rabbits in the early spring, or hungry deer year-round, and hail storms, wind and dust storms, T-storms and tornadoes, etc. at any time. Some months we might have a foot of rain, and then we might go three months with no rain at all. I guess the unpredictability of it all is one of the challenges. Sometimes I feel like I wake up in a different country every week here in the spring and summer time. Being informed is important, but so is being flexible and being able to "go with the flow" cause we never know what Mother Nature will throw at us.

    Happy Gardening,

    Dawn

  • shekanahh
    15 years ago
    last modified: 9 years ago

    Um......I cheated and ordered some little celery plants last year just for fun and planted them amongst some of my tomatoe plants.

    "Somehow" they grew about 12 inches tall, with thin stalks and spread out because I didn't tie them up or blanch them.

    They were a lovely bright green and were probably stringy, but I did harvest some of the tops for cooking, so all in all it was a fun experiment, but I probably won't repeat it this year.

    Actually, leeks and shallots are my big deal and challenge. Expensive to buy at the store, and the leeks usually taste like they've been stored in a tunnel for a year, all dank and nasty. There are just some things I refuse to buy at the market. Leeks and chard are two of those. :)

  • Okiedawn OK Zone 7
    Original Author
    15 years ago
    last modified: 9 years ago

    If you are in a part of Oklahoma that had a lot of rain last year (I'm not, unfortunately), it was a good time to try celery because, for once, the plants could get the moisture the need, although they still had to deal with more heat than they like.

    Do you grow leeks and shallots? They are so tasty from the garden. The reason most grocery store leeks taste like they've been in storage a long time is probably because they have been. Most root crops can be kept in cold storage for many, many months and for even longer periods of time if they are sprayed (as most are) with anti-sprouting chemicals (except for organic ones).

    I think that every veggie I grow tastes better than the stuff from the store. I won't even buy sweet corn or tomatoes from a grocery store because I am spoiled by the flavor of homegrown. I try to put about 200 ears of corn in the freezer every year, and would grow more if I had a bigger freezer.

    Saturday, I took a zip-lock bag of dehydrated cherry-type tomatoes out of the freezer, rehydrated a few and added them to a salad. Because they were so tasty, I then rehydrated a cereal bowl full and ate them by themselves. Yesterday I ate two bowls full. For a little while, as I munched on tomatoes, it "felt like summer" in the midst of winter.

  • hank1949
    15 years ago
    last modified: 9 years ago

    Dawn, you say:
    CAULIFLOWER: Plant from transplants between Feb. 15-Mar 10.
    CABBAGE: Plant from transplants between Feb. 15 and March 10th.
    BROCCOLI: Plant from transplants March 1-31.

    So when should one start germinating seeds inside to get the transplants ready on time?

    Hank

  • Okiedawn OK Zone 7
    Original Author
    15 years ago
    last modified: 9 years ago

    Hank,

    Well, here in southern OK, I start cool season transplants from seed about 4 to 5 weeks prior to their planting date. So, if I intend to set out the transplants in mid-Feb., I start them in mid-Jan. If I intend to set out the transplants in late Feb. to early March, I start the seeds inside in late Jan. If I were in OKC, I'd probably start seed for cauliflower, cabbage and broccoli around the last week in January or the first week in Feb., and would plan on transplanting the cabbage and cauliflower the first week in March, and the broccoli about the same time, or a little later. I always base those decisions on how cold the winter weather has been so far and on whether I think the cold will hang on later into spring (like it did last year).

    I have found that most cool-season crops transplant best when the plants are 3 to 5 weeks old. Once they are six weeks old or older, they tend to sulk a little longer after they're transplanted.

    Dawn

  • lovetotweet
    15 years ago
    last modified: 9 years ago

    I might have missed it mentioned elsewhere, but do y'all have favorite varieties of potatoes? In particular, we like to bake and boil them, and of course I love steamed red potatoes. :-)

    Thanks,
    Ada

Sponsored
NME Builders LLC
Average rating: 5 out of 5 stars2 Reviews
Industry Leading General Contractors in Franklin County, OH