By Sommer Cartier, for Let’s Talk Plants, September 2022.
Beat The Summer Gardening Slump
September can be a tricky time for gardeners in San Diego. Summer crops begin to wind down just as we enter the second month of our hottest period in San Diego - late summer/early fall. Selecting the right crop for this transition period can be challenging. There’s not enough time for new summer crops to mature and fruit yet, it’s still too hot to plant your winter garden. If you are feeling a summer slump, disillusioned by the lingering heat, I have good news. September is a perfect time to reinvigorate you garden. Remember, there are several quick yielding crops that grow year-round in San Diego and are great options this time of year.
For best results, this time of year, start your kale from seedlings in loamy, well-drained soil 12 to 18 inches apart. Keep the soil moist and cool to help preserve the sweep crisp flavor of the leaves. Side dress with compost every 4-6 weeks to protect the plant, keep the roots cool, and nourish it.
1. Lacinato, also known as Tuscany/dinosaur kale, has thick large leaves great for soups, is incredibly hardy, and can grow 5 or 6 feet tall.
2. Redbor has stunning magenta leaves with curly edges and mild, crisp flavor and texture.
3. Red Russian has smooth, tender leaves with purple veins and edges. It has a sweeter, more tender flavor, making it great for salads.
4. Common Curly Kale is what you commonly find in grocery stores. It’s known for its tightly curled leaves and slightly bitter, peppery taste.
Kale is usually ready for harvest 55-75 days from transplanting, depending on the variety. Harvest leaves from the outer edges of the plant to keep new leaves coming in for future harvests. Also remember to harvest greens young, before they become old, tough, and bitter.
Heat Resistant Lettuce
The lettuce family consists of four basic types: Butterhead, Leaf/Oakleaf, Crisphead, and Romaine. Within these families are varieties that tolerate heat and are slow to bolt. (Bolting is a term used to describe edibles and ornamentals that produce flowering stems and go to seed before they've been harvested.) In warmer temperatures, lettuce tends to shift its energy towards producing seed and the plant begins to grow upwards, becoming tough and bitter. By cultivating lettuce varieties that tolerate heat, you can extend your lettuce growing season and perhaps grow year-round. Below are popular heat tolerant lettuce varieties. Look for the words 'Heat Resistant' or 'Slow Bolting' on your seed packets. You can also purchase several of these varieties as seedlings at one of our local nurseries.
1. Butterhead: in general, butterheads are moderately heat tolerant.
· Buttercrunch Bibb
· Captain Bibb
2. Leaf/Oakleaf: generally, heat tolerant.
· Deer Tongue
· Lolla Rosa
3. Crisphead: tends to be more difficult to grow and do not agree with warm temperatures; some fare better than others.
· Lolla Rosa
4. Romaine: can be tough to grow in heat, though there are more heat tolerant varieties.
· Coastal Star
· Little Gem
To harvest lettuce, you can use the “cut and come again” method, removing only the outer leaves, or you can harvest the whole head at the base of the plant.
Swiss chard is easy to grow regardless of soil, day length or temperature. Its tolerance to warm, dry conditions which makes it a great leafy green to grow year-round in San Diego. Swiss chard does best in full sun however, if growing year-round, plant it in a partially shaded location with at least 4 hours of direct sunlight. Like kale, start your Swiss chard as seedlings in loamy, well-drained soil 12 to 18 inches apart. Side dress with compost every 4-6 weeks to protect the plant, keep the roots cool, and nourish it.
1. Bright Lights produces stems in yellow, orange, gold, pink, red, white, and striped. It’s leaves and stalks are tender and have a milder flavor than other varieties.
2. Fordhook has giant thick, greenish-white leaves that are heavily savoyed and quite tender.
3. ‘Rhubarb’ is a popular chard variety, named for its appearance and not flavor. This variety is not related to actual rhubarb. ‘Rhubarb’ chard produces dark green, savoyed leaves with dark red veins. The stalks are crimson and slightly flat.
Most Swiss chard varieties are ready to harvest in 50 to 60 days. For optimum flavor, harvest the leaves while they’re still glossy, removing two or three leaves off the outside of each plant. This will allow the plant to fill back in with new growth and leaves.
Now that you are equipped with the knowledge needed to beat the summer slump, get out there and start growing. Just remember, as San Diegans, we are fortunate enough to have several crops that grow year-round and can tolerate all seasons. There is never a bad time for planting when you select the right crops.