- Hardy vs. Half-Hardy Cool Weather Vegetables. Refer to page two of the Year-Round Food Gardening in Sonoma County publication to see what veggies can be planted in September and October. Not all of these veggies withstand the same degree of cold weather. Half-hardy crops (such as lettuce and cauliflower) can withstand a limited or light frost whereas hardy crops typically can tolerate a heavy frost (24-28 degrees F). If you want to harvest over the winter and/or early next spring, include hardy crops such as broccoli, Brussels sprouts, cabbage, collards, corn salad, garlic, kale, leeks, bunching onions, radishes, Daikon radishes and spinach. Also, note that most root crops can be "stored" in the ground as long as the ground doesn't freeze (for example, turnips and beets—unless you are growing them for their greens).
- Average First Frost Date. If you've lived in your current location for some time, you probably can estimate the first frost date based on past experience. But, if you're not sure, NOAA has you covered. They produce averages based on the past 30 years of collated data (updated every 10 years) for every weather station. We've made it a little easier to find this info by extracting the data for Sonoma County weather stations (see First and Last Frost Dates for dates based on different risk percentages in your area). Bring half-hardy veggies to maturity before this date and hardy veggies to at least near maturity by this date. As they say in banking, past performance is not an indicator of future earnings, but this is the best information we have for planning purposes.
- Ten Hour of Sunlight. At Sonoma County's latitude, we have less than 10 hours of sunlight from November 18 to January 23. During this time, crops imperceptibly grow or stop growing. If your area's first average frost date falls after November 18, use November 18 when determining when to bring a crop to maturity. Some hardy crops, if brought to a reasonable size by November 18, can be harvested throughout the winter and/or will begin growing again after January 23 for an early spring harvest.
- Days to Maturity. Every crop (and every variety) has a "days to maturity"—the days from when the seed or transplant is put in the ground to the date the first edible leaf or fruit matures. Usually you can find this information on the seed packet. If not on the packet, you will find it easily on the Internet. The date you plant and how you harvest (e.g., harvesting baby lettuce leaves) will affect your variety selection.
In the Garden
Etch Your Pumpkins.
It's Getting Hot, Hot, Hot!
Food Gardening With Less Water
During our hot, dry Sonoma County summer, food gardeners need
1) to provide enough water to their crops in order to replace the amount lost to surface evaporation and plant transpiration (the "ET Rate") AND
2) to do so in a manner that conserves water.
Food Garden Tips
September Food Garden Tasks and Tips
For what to grow this month, click here.
- Don’t stop weeding…they are still growing and competing with your vegetables for water and light.
- If you did not replenish the food garden soil last month, add two inches of good quality compost on top of the soil now. Why?
1) Compost builds soil structure by creating pores for air and water
2) improves moisture retention in light soil
3) improves drainage in heavy soil
4) feeds microorganisms that provide a symbiotic relationship between the soil and your plants so that plants can use the nutrients
5) provides all the nutrients in combination with the soil that your plants need. Higher soil nutrition helps plants produce better yields with the same amount of water!
- If September is hot, set out fall/winter vegetable transplants later in the afternoon and use a row cover for a week or two to protect tender seedlings from the sun. If possible, try to time transplanting veggie starts to coincide with the start of a cooler weather cycle, then watch to make sure they have adequate water when the temperatures go up.
- In Sonoma County, the summer food garden is still in high production. If you have an overabundance of squash, pick them when they are very young and tender. If you have more produce than you can use, your neighborhood food bank or a neighborhood gleaning program will be happy to help you out.
- Mulch will help with water retention and weed suppression now and protect against cooler weather in October and November. Use three to four inches depending on the size of the mulch particles. Mulch should not touch the plant stems. Do not cover seed beds with mulch.
- Stagger plantings of leafy greens and other favorite crops that can be harvested before mid-November (the average frost date for Sonoma County).
- Plant hardy crops that will survive the winter for a continued harvest.
- Remove the tips and small fruits of melons and winter squash as they won’t have time to mature. Also, pinch off the last blossoms of tomatoes, eggplant, peppers, and squash to encourage larger fruits.
- Clean up fallen fruit after harvest. Dispose of diseased material.
- Citrus: apply 1/2 pound 5-2-1 organic fertilizer mixed with 1 tablespoon Epsom salts per tree, then water well.
- Raspberries: foliar feed with liquid fish fertilizer twice this month.
- If you find snails and slugs in your garden, build a trap using a 12- by 15-inch board raised off the ground by 1-inch runners. As they collect under the board, scrape them off and destroy daily.
- Click here for ongoing monthly tasks.