Q. Last year we planted hot Hungarian peppers and broccoli in our garden and got hot broccoli. This year we have broccoli and jalapeño peppers and don't want the hot peppers to cross-pollinate with the broccoli like they did last year; same with our strawberries. How far from other veggies must jalapenos be planted to avoid cross-pollination? Thanks.
- ---Julia in Fulton County, PA
The first and biggest is that when cross-pollination DOES occur, it has no effect on the current year's plants. A single hot pepper plant will only produce that one variety of hot pepper as long as it lives. Same with broccoli, tomatoes, squash etc. Cross-pollination can only affect the seeds that the parent plants produce.
That's why it can be challenging to reliably save the seeds of garden plants that do easily cross-pollinate, like members of the squash family. Plant a pumpkin, a winter squash and a summer squash in the same garden (or even nearby gardens) and any seeds you save from those fruits will produce wild-card plants whose offspring can be a big surprise. (I once saved the seeds from a Connecticut Field pumpkin and got giant, ghostly-white birdhouse gourds when I planted those seeds the following year.)
But peppers don't readily cross-pollinate on their own. Like tomatoes, they require human workers to transfer the pollens from two different plants to create a hybrid variety with some of the characteristics of each parent. So your broccoli and jalapeños were incapable of affecting one another. Good thing, too, or we'd all have gardens full of weird mutant combos, like tomato-apples and pumpkin-flavored string beans.
In addition, pollination occurs when wind, insects or humans transfer pollen from one flower to another; and broccoli doesn't produce flowers—at least not if you harvest it on time. You didn't let your broccoli plants flower, did you?
Q. Unfortunately, we weren't quick enough—so yes, it did flower. But even the heads that didn't flower were hot; it didn't taste like normal store-bought broccoli.
A. Then we have a simple timing problem. There are three distinct garden seasons: Spring and Fall for plants that need cool weather and Summer for plants that can't take cool weather. Broccoli—like lettuce, peas and spinach—can't take the heat. But while pea vines just shrivel and die in the heat, crops like lettuce, spinach and broccoli 'bolt' and produce flowers.
When they do, they become hot, bitter and virtually inedible. But while the greens are lost for good (except for the potential seeds the flowers will produce), broccoli can still feed you through the summer and fall—if you utilize a super-cool trick.
For your Spring crop, select varieties that are labeled as somewhat heat-tolerant and get their six-week old transplants into naturally rich, compost-enhanced soil about two months before your weather typically gets real hot. In most parts of the country, that makes April Fool's Day the bull's-eye on the calendar. It doesn't matter how cold the soil still is, or even if you get a light snow or two afterwards; the plants are very cold hardy.
Apply a soil-cooling mulch of compost, shredded leaves, straw or other non-wood material around the plants, and have a heavy hand with the water when the weather turns hot. Lack of water will make broccoli taste hot, as it also does with garlic and hot peppers. (Chile heads who crave fire will deliberately under-water their plants a bit.) Feed your broccoli about a month later with more compost or a gentle organic fertilizer. Then slice the main head off the stalk at an angle (not flat) when it's full-sized, and while the unopened flower buds that make up the head are still tightly closed.
But leave the plant in the ground. It will continue to grow smaller heads called 'side-shoots' all summer long. Harvest these 'baby heads' quickly during hot weather, and then let them get bigger when the weather cools down. You can often get a total harvest that's four times as large as that first big head with this neat trick.
But many experts feel that Fall is a more ideal growing time for 'main crop' broccoli. Because the weather is always moving in the direction the plant prefers, you don't have the risk of bolting, and so aren't limited to varieties that can handle some heat. And because the soil will be toasty-warm at planting time, you can direct-sow the seed right in the garden. To time a Fall crop, add 45 days to the 'days to maturity' rating on the seed packet and plan to harvest right around the time of your typical first frost.
So let's say that your first average frost date is October 15th, and you've chosen a '60 day' variety of fall broccoli. You'd plant the seeds around the 1st of July, then thin the plants to about a foot apart when they have several true leaves. These young plants can take heat better than one with a fully formed head—and the hours of daylight are already on the decline at that time of year (boo-hoo!). Just be sure to keep the plants well-mulched and watered—especially early on.