Right crop, Right place, Right Time
Planting the right plant in the right place is an important sustainable gardening practice in any landscape. But, when food gardening, the right time also is essential. While there are perennial food crops, most of our home grown crops are annuals requiring either warm or cool weather to thrive and mature. Every crop has its own ideal soil and air temperature ranges for optimum germination and growth, but there are common characteristics within each category.
Cool-Season and Warm-Season Vegetable Crops.
- Cool-season crops grow best when seeded and transplanted in 60-65 degree soil and 65-75 degree air temperatures for maturing in cool, fall days. Cool season transplants can withstand soil temperatures as low as 40 degrees.
- Semi-hardy crops are those that survive a light frost, usually 36 degrees.
- Cold-hardy crops can survive a heavy freeze and will overwinter during a normal Sonoma County winter if brought to maturity or near-maturity in the fall. Most overwintering crops will survive at 25-28 degrees.
- Warm-season crops grow best in soil temperatures of 65-80 degrees and air temperatures of 65-95 degrees with little cooling at night.
- Some warm-season crops, such as tomatoes, eggplants and peppers, need extra protection to keep them warm if planted early in the season. Night temperatures below 55 degrees can have a detrimental effect on their overall growth and production.
- Select fruit varieties suited to your area’s chill hours—the number of hours below 45 degrees. Each fruit tree variety requires a certain number of chill hours in the winter to break dormancy for full production.
- Local nurseries stock fruit trees adapted to our climate.
- Successful crops with adequate chill in Northern California include apple, pear, prune, olive, and English and black walnut—as well as grapes, all grown here commercially.
The right plant is one that is seasonally suited for your growing conditions and microclimate, and is a crop that you and your family like to eat.
- Gardeners in inland microclimates with long, hot summers are able to bring a large late variety tomato to maturity but have difficulty with leafy greens in summer; whereas, gardeners near the coast are more successful with leafy greens and selecting an early season tomato variety.
- Every crop has a certain number of daylight (sunlight) hours needed to mature; some grow and mature best in warm weather while others prefer to start in warm weather but mature best in cool weather.
- Every crop variety requires a minimum number of days to mature before the end of the growing season.
- Besides food crops, it is important to include plants that attract bees and beneficial insects for pollination and to fight pests. These are always “right plants” in a food garden. In addition to planting flowers, allow some crops and herbs to flower after harvest.
The right place is dependent on microclimate and growing conditions as well as the choices a gardener makes regarding bed location/orientation.
- Locate food garden beds where vegetables will receive adequate sunlight.
- Leafy greens and many other cool weather vegetables require at least 3-4 hours of sunlight but more is ideal.
- Warm season vegetables require at least 6-8 hours of sunlight during the late spring and summer months, although full, all-day sun is ideal.
- When light requirements are not met, plants are stressed and more susceptible to pests and disease, and production will fall below expectations.
- Locate beds for good drainage; avoid low spots where water collects but where a water source is accessible for irrigation.
- Try to avoid cold spots, such as below a hill where cold air collects.
- Be aware of reflective heat such as that from south facing walls or rocks that may provide extra warmth or frost protection.
- Avoid shade from structures and large trees as well as invasive roots that compete for nutrients.
The right place also involves how a planting bed is oriented, where crops are placed and where crops are placed in a bed.
- Place crops with similar watering needs near each other, especially if using drip irrigation in the food garden.
- The most common orientation is east to west, planting tall crops on the north or west side so as not to block sunlight.
- On a slope, beds can run north and south with both sides exposed to sunlight.
- Shade within a bed from tall or trellised warm-season vegetables can be used to shield cool-season seedlings from hot afternoon sun in August and September.
- When lettuce is planted among bushy asparagus ferns in summer, dappled shade extends the lettuce harvest.
- The long-practiced combination of “the three sisters” has corn, pole beans, and squash planted together—corn supports beans; beans fix atmospheric nitrogen in the soil; squash leaves act as
Accurate timing, essential for an abundant harvest, is a matter of determining the intended harvest date and, then, working backwards determining when crops should be direct seeded or transplanted.
- Follow guidelines in the Master Gardener “Vegetable Planting Summary” (see link below) when selecting plants for warm-season and cool-season gardening.
- Plan hours of daylight. Plants grow unperceptively or stop growing when there is less than 10 hours of daylight. In Sonoma County, that occurs between Nov. 17 and Jan. 23.
- Plan to delay planting outdoors until after the last frost date in spring. In Sonoma County that occurs approximately Apr. 15; however, many gardeners plan on May 1. Dates vary in different microclimates.
- Consult seed packets, plant labels, and the Master Gardener “Vegetable Planting Summary” for the number of days to maturity and harvest. Allow enough time between harvest date and the planting date. Different varieties of the same crop may offer longer or shorter days to maturity.
- If a cool-season crop is direct seeded in fall rather than in spring, add 7-14 days to the days to maturity to account for the crop maturing during shorter days and cooler weather.
- The California Backyard Orchard (information about fruit tree requirements)
- Sowing Planting Calculation
- Sonoma Microclimates
- First and Last Frost Dates
- Vegetable Planting Summary