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Growing Great Broccoli and Cauliflower
February 15, 2015

Growing great broccoli in our climate region, along with most of the other brassica or cole crops, is just a matter of working with the weather to produce crops before and after the real heat of summer. Here in west central Indiana, we're able to grow great spring and fall crops.

Broccoli and cauliflower are heavy feeders, but don't really have to have ones very best garden soil. While we grow great brassicas in our raised beds with their improved soil, we also grow pretty good broccoli and cauliflower in our East Garden with its heavy clay soil. The trick with brassicas seems to be improving the soil around each broccoli plant a bit, feeding it well, keeping bugs off the plants, and beating the weather.

Transplants

plant rack
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Plant rack
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We grow our spring brassicas from transplants we start in February. Actually, we now grow all of our own transplants. We start more transplants inside during the heat of summer in June or July for our fall crop. While many vendors sell rather expensive plant racks and lightsicon, we still use a wooden plant rack I built in the late 1970s with simple fluorescent shop lights to nurture our transplants. The plant rack has moved with me through two marriages and four gardening locations, being torn down and reassembled at each new site.

While the photo at right shows a box for a plant and aquarium fluorescent tube, we generally use 5600° K and 6500° K fluorescent tubes for our plant lights, as they approximate daylight a bit better and are far cheaper than the plant fluorescent tubes.

A major advantage in growing ones own transplants is being able to choose from the many varieties offered by reputable seed houses, rather than just one or two offered by a garden center or other outlet. A second advantage is being able to time ones transplants to be about six to eight weeks old at planting time, an ideal growth stage for transplanting brassicas. One may even save some money by growing their own transplants over purchasing them, although with the cost of seed, potting mix, inserts and trays, and the lighting equipment, I'm not sure.

Starting broccoli, cauliflower, cabbage, and in our case, occasionally Brussels sprouts and kohlrabi, is pretty easy. Brassica seed germinates well in the dark without any bottom heat.

Deep sixpack and fourpack inserts side-by-sideWe start our plants in standard 1020 seed flats in #804 or deep #606 inserts from the Greenhouse Megastore (DGW rating). While those terms may sound like gobbledygook, it means I use plastic inserts that give me 8 fourpacks of cells which equal 32 planting cells per seed flat or six deep cells per insert which equal 24 cells per seed flat. Such insert cells hold enough soil to adequately nourish transplants such as brassicas, tomatoes, peppers, and such for six to eight weeks growth from seeding to transplanting. Keeping the plants in such small quarters any longer than that risks stunting their growth.

I usually use a slotted seed flat for drainage directly under the inserts with a solid flat (no holes in the bottom) underneath the slotted tray to catch runoff. The second flat also adds a little strength to the combined flats, although in recent years I've also begun using a slotted tray with a heavy-duty Perma-Nest tray underneath it. For smaller plantings, I use some old half flats that hold four, four cell inserts.

We wash and reuse our seed flats and inserts year after year until they split, crack, or get stepped on.

804 insert in slotted and solid seed flats 804 insert in slotted 1020 tray and perma-nest tray Soil sterilization pot and half flat

Since brassicas transplant quite well, one could also start their broccoli (cauliflower, etc.) with a dozen or so seeds in a single pot, transplanting the seedlings when they've emerged and put on their first true leaves into larger, individual pots or four- or sixpacks. As long as the plant container has enough room for root growth and good drainage, the plants don't seem to mind what they're in.

I fill the inserts with sterile potting mix, often on our back porch on a nice winter day, and firm the soil with my hand. I water the potting mix with warm water, as the peat moss in our starting mix doesn't readily absorb cold water. Sometimes I water the whole flat before seeding and split away the bottom solid tray for a time to let excess water drain. At other times, I seed into dry soil, pull the slotted flat up, and bottom water the trays, later draining any excess water. Either way, I have to warm the water used on our stove, as our hot water is soft water that contains some water softener salt. The small amount of salt in soft water probably wouldn't hurt the plants, but it's one more thing I can do to ensure good germination and growth.

Seeding Amazing CauliflowerHalf flat of planted cauliflower covered by humidomeThe seeding process is just a matter of making a shallow indentation in the center of each insert cell with a finger or thumb, popping in a seed, and covering the seed with a little sterile potting mix. I often add an extra seed here and there at the corner of a cell in case some seeds don't germinate. I label each fourpack insert with a plastic plant label with the variety name. We cut costs by reusing the plastic plant labels year after year, soaking them in a bleach solution to remove the permanent marker ink on them. Surprisingly, the labels last four or five years before becoming brittle and snapping in half!

The planted flat of brassicas is covered with a clear humidome to hold in moisture and goes onto a shelf on our plant rack. While light isn't needed to germinate brassicas, I want the plants to begin getting light as soon as they emerge (four to six days, usually). Once our transplants have pretty well all germinated, we remove the humidome and quickly get our plant lights within a few of inches of the tops of the plants. Our brassicas are often a bit spindly at first, and sometimes I have to carefully uproot them, moving them deeper into the soil without injuring the plants to correct the initial legginess.

Brassicas up

We generally (bottom) water our plants about once a week after they germinate with about a half gallon of water per planted seed flat. In three to four weeks, the plants are big enough to be moved outside under our cold frame.

Hardening Off

At four or five weeks old, brassicas may appear to be big enough to go into the garden, but they're not quite ready yet. The plants have to gradually become acclimated to the harsher growing conditions of the great outdoors. Putting them under a cold frame keeps the plants a bit warmer (a lot warmer with the top down) and protects them from the full sun, UV radiation, and wind. Opening the cold frame for gradually longer periods each day allows the plants to toughen their stems. Gardeners lacking a cold frame can harden off plants in sheltered areas of a porch or similar area.

Cold frame propped open Transplants under cold frame

After a week to ten days, if I'm not ready to transplant our brassicas, they go on the edge of our back porch, fully exposed to the sun, wind, and rain...and do just fine there. I do have to remember to water them regularly.

Warning: Leaving plants under a closed cold frame on bright sunny days can cook ones transplants. A good cold frame will trap enough heat to shoot interior temperatures well over a hundred degrees on such days. Been there, done that, and I didn't even get a T-shirt, but I did kill a lot of transplants!

Preparing the Bed

Soil pH test meterGardeners work with the soil they have, hopefully gradually improving it over the years by adding compost, peat moss, and/or turndown crops. But whatever soil one has, it's important to loosen the soil before planting or transplanting by rototilling or using a shovel, garden fork, and/or garden hoe. While doing so, one can work in any soil amendments necessary. Soil pH for brassicas should be around 6.8-7.0. Lime to raise soil pH is best added in the fall to give it all winter to work. One can use ground limestone in the spring, which works more quickly than granular limestone to adjust soil pH. Sulfur can be used to lower soil pH, something we in the midwest only do when planting potatoes and such. A general fertilizer such as 12-12-12 can be lightly broadcast over a planting bed and worked in while tilling.

An inexpensive soil test meter for soil pH is a good investment. They're fairly accurate and last for years.

We save ourselves a lot of grief by fall tilling our garden plots, especially those that will be used early in the spring for early peas and brassicas. We still find spring tilling necessary some years, but get away with just a good hoeing and raking other times.

Transplanting

Broccoli and cauliflower get bitter and go to seed in the heat of summer here, so our brassicas are always the first plants we move into our garden. Since brassicas can withstand a light frost, we usually get our broccoli, cauliflower, and cabbage transplanted in early April, although they've gone in as early as March 24 and as late as May 25 in the spring. But over the last few years, we've found planting during the first week of April to be about the right time to transplant in our area.

Prepping hole for brassica transplantPaper cup cutworm collarOnce any necessary soil preparation is done, our brassica area is raked smooth and stakes and string are added to assist in getting our rows straight. I use a wide garden trowel to dig a planting hole as deeply in the soil as I can (about 6-8"), loosening the soil at the bottom of the hole as much as possible to promote deep root growth. Then the transplanting hole gets a quarter handful of 12-12-12 commercial fertilizer and a sprinkle of ground limestone to fend off clubroot. I use my trowel to work both into the soil a bit. Then I fill the hole with dilute transplanting solution (about half strength Quick Start, with a bit of Maxicrop Soluble Seaweed Powder mixed in).

Once the starter solution has soaked into the soil a bit, I backfill the hole with the soil I dug earlier and plop a "cutworm collar" into the soil and water the cup. Since we have problems with cutworms in our garden plots, I use old, waxed paper coffee cups with the bottoms cut out as cutworm collars. Left in place for a week to ten days at about an inch above the soil line, the cups prevent cutworms from attacking the still tender brassica stems.

Then I squish my transplant into the cup, backfilling with a bit more soil around the base of the broccoli stem. I use my fingers to firm up the soil and again water generously with starter solution.

Transplanting cauliflowerThree foot row spacingIn our current raised beds, we space our broccoli plants about 18-20 inches apart in the row, leaving anywhere from eighteen inches to three feet between rows, depending on where and what bed they're going into. When planting into our narrow raised beds, a close row spacing of 18-20 inches is necessary, as the bed is only 36" wide, and I'll probably want to edge it with flowers or spinach. When planting into our main raised bed or our East Garden with more space, I often leave two to three feet between rows of brassicas. I get away with the closer row spacings because I only plant two rows of brassicas together, allowing me to work the plants from the outside of the rows. If one is going to plant more than two rows, a spacing of 30-36" between rows allows one to work the rows and later harvest the crop without damaging plants.

When I can, I try to space our cauliflower and cabbage a little more in the row, as those plants tend to spread more than broccoli. But more often than not, I'm cramped for space and space them about the same as the broccoli.

An optional, but for us, necessary, step in the planting is to spread some smelly, nasty tasting stuff on the plants and ground to discourage rabbits and deer from nibbling on the plants. It also keeps our dogs, usually, from digging up the transplants or laying on them.

In poor soil such as our East Garden, I work in a shovelful of peat moss to each planting hole along with the fertilizer and lime. I essentially improve the soil in a one foot diameter circle about a foot deep where the broccoli or cauliflower will go.

Care Through the Growing Season

Pulling one side of cupMulched brassicasAbout a week or so after transplanting, I'm able to remove the paper cup cutworm collars from the transplants. I use a quality pair of kitchen shears to cut down the sides of each cutworm collar. Then placing fingers on the soil on either side of the plant stem, I very gently pull each half of the cup up and out of the ground. I firm the soil to fill in the space the paper cup occupied and water the plants.

If I haven't already, I begin mulching our brassicas with grass clipping mulch. It holds in soil moisture and mostly prevents weeds from germinating under the plants and in the rows between them. The mulch breaks down in time and has to be replenished at least once before harvest. But as the mulch breaks down, it also adds nutrients to the soil. With mulch, we don't have to water our brassicas once they get established.

Depending on how fertile ones soil is, you might be able to get away without any additional fertilizer until harvest. But brassicas are heavy feeders, so pulling back the mulch and working in a bit of balanced fertilizer and/or compost around the base of plants can give them a boost.

Insect Problems

Once you get past the danger of cutworms at planting, there is another major insect problem with growing brassicas. The worms from cabbage loopers or small white cabbage moths can make brassica leaves look like someone blasted them with a shotgun while also seriously damaging the heads. The moths lay their eggs on brassicas and when they hatch out, the worms have a ravenous appetite.

The safest, best prevention for such insects are products such as Thuricide and Dipel that contain the biological, bacillus thuringiensis (BT). Unlike typical poisonous insecticides, BT acts by producing proteins that give the bugs fatal stomach cramps. Their digestive system gets paralyzed, and the infected insects stop feeding within hours and generally die in a few days.

We spray with Thuricide throughout the gardening season to keep our broccoli, cauliflower, cabbage, and kale fairly worm free. BT is considered safe to people and nontarget species such as wildlife. And it can be used on a variety of food and other crops. We've had good results using Thuricide to prevent bag worms from attacking our Blue Spruce trees.

As with all controls, BT sometimes fails. When that happens, usually about once a growing season with our kale, I have to break out some stronger stuff to vanquish the nasty worms.

Critter Damage

Both rabbits and deer can devastate a planting of brassicas. Rabbits will eat new transplants right off to the ground. Deer wait a little longer, biting the tops off of broccoli plants when the plants are about a foot tall. As mentioned earlier, smelly, bad tasting stuff is often enough to discourage critters.

Even with the best preventions, though, you sometimes lose. Several years ago, rabbits ate every one of our fall brassica transplants right off to the ground. Only a couple of the plants recovered and regrew from the roots, although we still got a small crop of broccoli by direct seeding.

Buttoning

Buttoning is the failure of broccoli plants to produce heads or producing small heads prematurely. We'd seen a bit of buttoning every now and then in a plant or two in our garden. In the spring of 2016, seven of the ten broccoli transplants I'd set out buttoned! Stress is listed as the cause of buttoning on most sites, with cold temperatures, poor soil fertility, root bound transplants, dry soil conditions, and excessive salt in the soil all being mentioned.

Plants that have buttoned can be left in the ground to possibly produce sideshoots later on and may even put on some usable heads.

 

Harvest

Cauliflower (Amazing)
Broccoli sideshoot

Mature broccoliIn a good year, the broccoli we transplanted into our raised beds in early April begins to mature good heads in mid-May. The leftover transplants we put in later in our East Garden put on main heads in June. Our cauliflower with its longer days-to-maturity begins to come in about a week or two after the broccoli. But both crops can defy days-to-maturity figures due to weather conditions, coming in either early or late. And broccoli, once it sets a head, can mature very quickly, making daily checks of the crop important.

We cut our broccoli when the heads are still tight and a nice blue-green color. Waiting until the buds begin to open into yellow flowers or the head browns a bit ruins the broccoli. We take our cauliflower heads when they're just a little bigger than a softball. Once the leaf wrap around the cauliflower begins to spread, it's time to cut it, as sunlight will cause the heads to yellow and turn bitter. Since we grow varieties that have been standardized for a concentrated commercial harvest, our broccoli tends to come in all at one time. Since broccoli freezes well, that's not a real problem.

Bowl of sideshootsThe actual harvest of the broccoli and cauliflower is done the same way. We use a sharp kitchen knife to cut just below the heads. Once cut, the cauliflower plants come out of the ground to be composted. Broccoli plants are usually left in the ground and even fertilized a bit. They will begin to put on smaller sideshoots (mostly quarter sized heads, but sometimes larger) that can extend ones picking season for several weeks. As long as the weather doesn't get too hot, the sideshoots should be as sweet as the main heads. They're just smaller, take a bit of hunting to find, but there should be lots and lots of them.

Broccoli and Cauliflower

Varieties

Violet of Sicily cauliflowerBrassica varieties, especially broccoli, seem to come and go over the years as seed producers move on to newer hybrid varieties. Varieties that grow well here in the midwest may not grow as well in other regions. Having said that, our longtime favorite broccoli is Premium Crop, a hybrid whose seed is getting hard to find. Goliath, another hybrid, produces large heads for us, again with a concentrated set, something not always wanted by home gardeners. Some open pollinated varieties, such as the Italian heirloom, De Cisso, produce smaller main heads spread over a longer period of time, followed by many sideshoots. We've not had much luck growing De Cicco, though.

Fortunately, our favorite cauliflower is an open pollinated variety, Amazing, that self-wraps its leaves to keep heads from yellowing. Dedicated seed savers should keep that variety around forever. Fremont is a good producing hybrid that we use as well. And we just "discovered" the old Violet of Sicily variety, which produces medium sized heads that turn reddish at maturity. Note that Violet of Sicily seems to be available from some vendors under similar names (Purple of Sicily), but you'll know it by its appearance in pictures in seed catalogs.

Other Brassicas

We don't grow a lot of cabbage in the Senior Garden, but what we do grow is usually Alcosa savoy, Super Red 80, Tendersweet, and on occasion, the tried and true open pollinated Early Jersey Wakefieldicon. The same goes for kohlrabi, but we use Grand Duke (which has been replaced by Winner in seed catalogs).

Our favorite kale is Vates (also called Dwarf Blue Curled and Dwarf Blue Scotch). It's been our standard kale for years and is a solid producer with very good flavor. We also grow some Lacinatoicon and Red Ursaicon. We direct seed our kale, spring and/or fall, as it doesn't seem to transplant as well as other brassicas. Getting fall kale started in our hot, dry, July weather can be a challenge, requiring daily watering.

Possibly because it's not one of my favorite vegetables, we don't grow a lot of Brussels sprouts. The Churchill variety always starts out well for us, but it seems the bugs and heat almost always get the sprouts before we do.

Fall Brassicas

Other than the timing, we grow our fall brassicas just as we do our spring broccoli and cauliflower. We start our transplants inside in late June while we're still feasting on spring broccoli and cauliflower. After hardening off, the plants go into the garden in late July or early August. (Note that I do rototill the bed before transplanting, adding a good bit of compost and/or fertilizer.) We experience a lot more rabbit damage with our fall brassicas just after transplanting, though.

First row in Mulching the bed Planted and mulched

We also have to water our fall transplants a few times to get them established mid-summer, as our soil gets pretty dry by July. Getting grass clipping mulch around the transplants as soon as possible reduces the need for watering. When mulching right after transplanting, care must be taken to not let the mulch form a ramp up to tops of the cutworm collar cups, as cutworms will gladly march up it and consume your precious transplants.

With fall cauliflower, it's especially important to allow at least two to three weeks more than its days-to-maturity before the first expected frost. Fall planted crops grow more slowly in the shorter days of fall. We've flat out missed on this one several times, getting good fall broccoli, only to lose our fall cauliflower to a hard freeze a week or so later.

Saving Brassicas

AmazonWhile we've canned and frozen vegetables for many years, I feel a little on thin ice on this section. When we put up broccoli, cauliflower, or any other brassica, we scrupulously follow the directions in the Ball Blue Book Guide To Preserving. It is THE ESSENTIAL SOURCE about safe canning, freezing, and other methods of preserving.

After cutting broccoli or cauliflower and washing and stripping off the leaves, we soak it in salt water for half an hour to kill off any worms that have survived our efforts with BT. Then we cut the broccoli or cauliflower into florets or individual mini-heads, leaving a bit of head with several inches of stem to be frozen. Even with our best efforts at insect control, we often find a dead worm or two in the florets to be disposed of.

Blanching broccoli (Lid off only for photography)The broccoli (or cauliflower) then has to be blanched or scalded for 3-5 minutes to kill off bacteria that might be present and quick cooled in a sink of cold water before drying. I just spread the broccoli out on a clean kitchen towel for drying.

Broccoli frozen and some ready for freezingWhile one can stuff the broccoli into a freezer bag at that point, I prefer to spread the broccoli out on a no-stick cookie sheet or one treated with spray cooking oil for freezing. That makes taking a few florets out of the freezer bag a bit easier later on.

Once the broccoli or cauliflower has frozen on the cookie sheet, I put the florets into a gallon Ziplock Freezer Bagsicon, squeezing out as much air as possible before zipping them shut. Then the bag goes into our big, manual defrost freezer in the garage.

Most of our kale gets used fresh or in our Portuguese Kale Soup. When we're able to freeze some, it gets soaked, stemmed, inspected for worms, blanched, and frozen with liquid in pint freezer bags.

Walmart iconLet me insert a commercial note here. I use a Tramontina 8-Quart Multi-Cookericon for such blanching and a lot of other things. It's one of the very few, expensive pieces of cookware I use. I bought ours around ten years ago when the cost was about half of what it is today. Unlike some cheapie cookware, the pot is quite heavy, which helps spread heat evenly and prevent burning along the bottom. The set comes with two strainer/steamers. I love ours.

Having written all this stuff about freezing, I need to add that frozen brassicas are a poor second best to fresh. We love steamed broccoli, cauliflower, and carrots with garlic, seasoned salt, and lots of butter. But there's nothing quite like fresh broccoli, cauliflower, or kale. (Note that I'm writing this update in the dead of winter, just after we used up the last of our frozen kale!)

Help with Timing Crops

Several years ago, the folks at Johnny's Selected Seeds began publishing a page of Interactive [Garden] Tools. I find their online Seed Starting Date Calculator and their Fall Harvest Planting Calculator spreadsheet (589K download) especially helpful in timing planting or starting transplants. They're free and easy to use.

Final Thoughts

Broccoli may have been the first garden crop I really mastered growing well. It's either that easy, or I just got very lucky over forty years ago. I didn't grow good cauliflower until five or ten years ago, helped along greatly by the advent of self-wrapping varieties. And "mastered" may be a relative term, especially when you see an open garden plot where rabbits have eaten every transplant you painstakingly put out. Or, when you get greedy and decide to let a gorgeous row of broccoli plants go a few more days to reach soccer ball sized heads...and it all goes to seed the next day.

Gardening for me has been a lifelong learning process. It began as a five-year-old following my grandfather around his one acre garden in then rural Indianapolis (really in Nora, for folks familiar with Indy). I began my own garden plots in our back yard before my teenage years, growing strawberries and sweet corn. When we had our first house with a yard, our landlord and my former foreman on the loading docks loaned me his rototiller and his Burpee Seed Catalog. I've been lost forever after in the wonder of gardening.

Having said all of that, just because a retired, old guy has a web site on gardening doesn't mean he knows jack about it. I have absolutely no degrees in agriculture or horticulture or any other special training. At 68 years old, I'm still happily learning, so there could be tragic errors in the information above. It's just what has worked for us.

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From Steve Wood, the at Senior Gardening

 

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