Thriving cool-season crops
Several crops thrive in cooler temperatures, including cilantro, artichokes, broccoli, cabbage, kale, carrots, garlic and onions, among others. For a complete list of cool-season vegetables suitable for our region, see the UC Master Gardeners' Vegetable Planting Guide for Fresno County Gardens.
Most of Fresno County is in USDA Plant Hardiness Zone 9, which gives us distinct advantages for year-round gardening. According to UC Davis, the Fresno area enjoys 246 frost-free days at 32°F or higher, and 300 days with temperatures at 28°F or higher. This extended growing season affords gardeners ample opportunities to continue cultivating plants well into the cooler months.
To start cool-season vegetables, you may need to germinate seeds indoors or in a greenhouse, where soil temperatures can range between 55°F to 65°F. Once the seeds have germinated, transplant the seedlings into larger containers or directly into your garden soil. For crops like garlic and onion, you can plant sets directly into the soil, spacing them about 6 inches apart.
Cilantro, in particular, flourishes in cool weather and performs best at temperatures below 80°F. When temperatures rise above this threshold, cilantro may bolt (flower) prematurely, resulting in a bitter flavor.
Soil and fertilization tips
When transplanting your cool-season plants, ensure the soil is well-draining to promote healthy root development. You may add perlite to your potting soil to obtain the desired drainage consistency.
For optimal growth, it is advisable to fertilize your plants with a balanced 10-10-10 fertilizer. The numbers on a fertilizer bag represent the percentage of nitrogen (N), phosphorus (P), and potassium (K), each of which serves a specific purpose:
- Nitrogen (N) promotes leafy growth.
- Phosphorus (P) supports root and fruit development.
- Potassium (K) strengthens stems, improves pest resistance, and encourages overall plant vigor.
Different formulations of fertilizer are available, depending on the plant's needs at various growth stages. For example:
- 10-10-10: A balanced fertilizer suitable for any stage of plant growth.
- 10-20-10: High in phosphorus, ideal for flowering, fruiting, and root development.
- 20-10-10: Rich in nitrogen, best for encouraging leaf growth and color.
- 10-10-20: High in potassium, which supports robust roots and stems.
Conclusion
By embracing the opportunities offered by cooler weather, gardeners can extend their growing season almost year-round. With proper planning, planting and care, you can enjoy the rewards of your gardening efforts well into the colder months.
Happy gardening, and may your vegetable harvests flourish!