Growing broccoli in Oregon can be a rewarding experience for home gardeners looking to harvest this nutritious vegetable either in spring or fall. Timing your planting correctly is crucial, as broccoli thrives in cool weather. In the state's various hardiness zones, understanding the frost dates — such as the median last spring frost of April 11 in Zone 6b — can help you achieve optimal growth and flavor.
In Oregon, you have the chance to plant broccoli for a spring harvest or for a fall yield, depending on your region's climate. If you're in areas like Gresham (Zone 7a) with a last spring frost of March 23, you can start planting early. Conversely, in Zone 6a locations like Albany, where the last frost falls around April 22, scheduling your indoor starting and outdoor transplanting will differ significantly.
By carefully planning your sowing and transplanting windows, you can ensure a bountiful harvest of this delicious vegetable. With cooler temperatures ideal for head formation, it's vital to manage environmental factors, so keep in mind your local growing conditions. Follow this guide to successfully grow broccoli, and you'll enjoy its fresh, flavorsome heads for many meals to come.
| Zone | Indoor start | Transplant out | Direct sow | Harvest |
|---|---|---|---|---|
| Zone 6b | Start February 15 – March 1, ~6–8 weeks before April 11 | Transplant outdoors from March 31 – April 14, after frost risk has passed | Direct sow from April 15 – May 1, post frost limitation | Harvest June 15 – July 15 for spring planting, and from October 1 – October 15 for fall planting |
| Zone 6a | Start March 1 – March 15, ~6–8 weeks before April 22 | Transplant outdoors from April 23 – May 7, once temperatures stabilize | Direct sow from May 8 – May 22, allowing soil to warm sufficiently | Harvest July 1 – August 1 for spring planting, and October 15 – October 31 for fall planting |
| Zone 7a | Start February 15 – March 1, ~6–8 weeks before March 23 | Transplant outdoors from March 24 – April 7, when the risk of frost is minimal | Direct sow from April 15 – April 30, giving plants the best start | Harvest June 20 – July 20 for spring planting, and produce from November 1 – November 15 for fall harvest |
If you're in a colder area, pay extra attention to frost dates. You may need to delay transplanting or choose shorter-maturing varieties to ensure successful growth.
While May is generally late for planting spring broccoli, you can still direct sow for a fall harvest if you choose fast-maturing varieties. Just be cautious of high summer temperatures.
Harvest broccoli when the heads are dark green and tightly packed. Look for yellow flowers, which indicate it's past peak quality. Timing your harvest is essential for the best taste.
Once broccoli bolts, it typically means temperatures have risen too high. If this happens, cut off the flowers and consider planting again in the fall, focusing on varieties suited for cooler weather.
Using row covers can protect young seedlings from pests such as cabbage worms. If pests persist, consider organic treatments like Bt to safely control caterpillar infestations without harming beneficial insects.
Typical fall sowing window for Broccoli in Oregon: September 2 – September 2.