Below is a copy and paste of selected text regarding spring growing of broccoli either from seed in ground, starts/transplant or store-bought transplant. Also good varieties of bolt-free or bolt-less broccoli to grow in Oklahoma.
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.
Here's what normally works for me:
1) Grow your own transplants. You want them to be 4 to 5 weeks old when you transplant them into the ground, and you want to have 4-6 leaves on them. Any smaller or larger and they tend to bolt. Keep them consistently moist and feed them with a water soluble fertilizer, whether organic or synthetic in nature, so that they are not stressed while young. I believe that the reason purchased transplants bolt so often is that they were allowed to get too dry or too hot or too cold before you purchased them, and that's why I started raising my own.
2) Transplant at the proper time. This can be hard since we don't know what the weather will do. Broccoli is a biennial. If you have "late" cold weather after the broccoli has reached a certain size (roughly 4 to 6" tall), and the plants are exposed to a certain number of days (roughly two weeks) of temperatures in the 40s, they go into a dormant growth stall and just sit there. Then, when it warms up again, their perception is that they now are in their second season, so it is time to set seed to perpetuate their species. Thus, they bolt. You cannot control the temperatures and you cannot change the inherent nature of biennial plants, so when the temperatures are the cause of bolting.....there isn't much you can do. I tend to plant slightly later than recommended (the recommendation is to plant broccoli roughly two weeks before the average date of your last frost, but I often wait until a week after) in a year when I expect cold weather to hang on, and slightly earlier than usual in a year when I expect an early last frost and an early warm-up, like we had last year.
One reason it is so hard to get a good harvest from cole family crops here is that our cool season is too short, or as I often say, we go from too cold to too hold just too quickly for them.
3. Protect your young broccoli plants from any temperatures outside their ideal range of 40-75. Cover them up on cold nights, shade them on extra hot days. Doing this helps keep the cooler or hotter temperatures from inducing bolting. It is not necessary to do this step some years. But, most years, if you can protect the broccoli plants from the very cold and very warm temperatures, it greatly reduces the likelihood they'll bolt.
Ideally, in a perfect garden in a perfect world, your broccoli will give the best harvest when it grows and matures while the temperatures are between about 40 degrees and about 75-78 degrees. Ha, ha, ha! How long do we have temperatures like that here in this state? The answer is: not long enough.
If you were growing an open-pollinated broccoli variety, you can save seeds. Just let the plant flower and leave the flowers on the plants until they are dry before you collect the seeds. If you are growing a hybrid variety, seeds saved from it likely will not come true to type and might not be worth saving.
Some varieties of broccoli tend to bolt more than others. Packman is a variety that doesn't bolt very often if I raise them from seed but they always bolt when I purchase them. In recent years I've also grown Piricicaba, which doesn't make big heads, but also doesn't bolt. In 2011 in the hottest most miserable summer most of us ever have seen here in OK, the Piricicaba was at the western end of the garden where it got afternoon shade from a pecan tree to its west, and it survived that summer, even when I didn't water for two months and almost no rain fell, and it rebounded nicely in the fall and produced until December.
This year I am trying Coronado Crown and Summer Purple in addition to Packman and Piricicaba. So far, none of them have bolted.
mulberryknob adds:
A thought occured to me for the broccoli newbies to tell when broccoli is going to bolt. I was in the garden of a friend the other day and her broccoli was not blooming yet, but getting close. She was waiting for the heads to get bigger, like she sees in the stores. You can't go by the size of the heads. You have to look at tightness of the florets and stems on the heads. Hers were getting loose, with the stems of the head opening up but not yet showing yellow flowers. I told her to pick the top head that day, water and fertilize and wait for the side shoots.
I said I don't let my broccoli bolt. That's because even if the heads are really small, when they loosen up a bit I pick them, and wait for side shoots in a year like this. (In most years I get big heads and rip the plants out after the main head is picked.) Someone said that the individual buds should be about the size of a grain of rice. All the buds aren't the same size at maturity, but that's a pretty good rule. I think everybody who grows broccoli ought to let one plant go through its bloom phase just so you know what the various stages look like. Then the next year you'll know when to pick.
broccoli is one of those plants that I prefer to use hybrids. That's because the DTM (days to maturity) is shorter for hybrids. Packman, a reliable producer here, has a very short DTM. It is hybrid.
Dawn on Direct Sowing:
You can direct seed broccoli in the garden if you like, and you may have good results in a year with a long, cool spring, BUT the preferred method is to set out transplants.
I have done it both ways, and always get better results from transplants. I did have one year in Texas (before we moved here) where I got an amazing harvest from direct-seeded plants. It was during an El Nino year in the mid-1990s and the weather stayed cooler and rainier than normal all spring and for most of the summer. Results like that, though, are the exception and not the rule.
The difficulty in growing broccoli in our climate is that it grows best when the temperatures are in the 40s to the 70s, and we have a limited window in which our late winter and spring temperatures fall within that range. Just a few days with highs in the 80s can cause broccoli to bolt and go to seed, and then you don't get much of a harvest once that starts happening.
Our highly variable spring temperatures make the growing of all cool-season crops challenging as the occasional hot days cause all sorts of problems. That said, broccoli is not at all hard to grow as long as the temps cooperate.
The problem with starting broccoli from seed sown directly in the ground in our cold winter climate is that it is slow to germinate and grow in soil temps in February or early March when it ought to be planted, which gets it off to a slow start. Transplants will give you a harvest 3 to 5 weeks earlier than direct-sown seed most years, and since we barely can get a good harvest most years before the heat arrives, that 3 to 5 week difference is huge.
Annie writes:
I have great results growing BROCCOLI here in Central Oklahoma. I even have it do well into June or July and not bolting. I pick off the little broccoli side branches clear into July many years.
I mulch it deeply and water it deeply. I grow huge, tender broccoli heads.
I have direct-seeded broccoli, but like the others have said, have gotten better luck starting them indoors or in cold frames and transplanting them out.
I have not had good results in direct-seeding them out in rows, but I have started them in mass plantings in a cold frame or in a bottomless pot or wooden box sunk into the soil. Sprinkle in seeds, lightly cover and water well. Cover with plastic sheeting or an old window sash. Remove cover during the day if it is sunny and temps above 40 degrees. Cover them at night. You can transplant them out into the garden where you want them to grow after all chance of hard freezes have past.
Dawn:
BROCCOLI: With all the cole crops, you need to get transplants into the ground as early as you reasonably can without subjecting them to temperatures that will kill them (for broccoli, that usually is around the mid-20s). Once the temperatures get too hot, they'll bolt, which means they will quickly flower instead of forming the large broccoli heads you want.
Unless specified, the advise given was provided by OkieDawn
10 years ago
10 years ago
Okiedawn OK Zone 7