Spring Broccoli

I have been growing broccoli in the late winter and spring for several years. Last February, I sowed broccoli seeds, and I planted broccoli transplants that I purchased from a nursery. I planted the nursery transplants directly into one of my raised beds in early Feb. I sowed the broccoli seeds in an outdoor pot filled with new potting soil in med-Feb. Contrary to what I said in a previous post several years ago, most of the broccoli seeds sprouted outdoors in about 2 weeks without difficulty in our relatively mild February weather. I then transplanted the seedlings from the pot into another raised bed in early March, about a week or 2 after sprouting. I mixed organic fertilizer (blood meal, worming castings, etc.) into the soil prior to planting the seedlings.

This year, the plants that I grew from seeds have grown bigger and produced larger crowns than the nursery transplants. The pictures below are some of the plants I grew directly from seed. These crowns are as large or larger than the typical broccoli crowns I see in grocery stores.

The nursery transplants produced small crowns in late April and early May. The plants that I grew directly from seed are mature now. In the past few years, they have continued to produce smaller crowns well into summer. Even though I planted too many of the seedlings too close together, the broccoli plants I grew by seed, including and crowns, have grown as large as ever.

I think the success of my broccoli by direct sowing can be at least partly explained by the fact that I was able to time the sowing of the seeds to cause the crowns to mature at the optimal time for our climate. Broccoli thrives in full sun and long days, which is why broccoli grows so large in southern Alaska during their growing season when days have 18 or more hours of sunlight. But broccoli does not thrive in heat. Its ideal growing temperature range is about 60-75F. Therefore, the ideal time for broccoli to mature is in late spring or early summer right before consistent hot weather (80 F+) sets in. In our climate, that time is late May to mid-June. Broccoli seeds should therefore be planted here in Mid-Feb. 90-100 days prior to the target harvest time.

Nursery transplants are often sold too early, at least for my area. Hot weather starts at different times of the year in our different local micro-climates. In areas that have many micro-climates, nurseries may not sell the transplants at the best time for all of the nearby micro-climates.

Another reason that nursery transplants may produce small crowns is if they are root bound. Broccoli plants that have become root bound in a pot have lost valuable growth time. Although they recover and continue to grow after being transplanted, they don’t have as much time to grow as large as they could. For these reasons, I have defaulted to sowing broccoli seeds rather than purchasing transplants. Even though it is more work, the reward has been worth it.

May 29 2018 10:16 pm | Broccoli