Is Swiss chard a perennial or annual plant?
Written by
Nguyen Minh
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.The growth habit of Swiss chard often confuses many gardeners. In frost-free areas, Swiss chard acts like a biennial, whereas in cooler temperatures, it grows like an annual. It is very cold-tolerant and can survive below freezing through winter down to 15°F, and with good protection, it can endure more frigid temperatures. In fact, even in cooler regions, Swiss chard will grow for 8 to 10 months, producing an endless supply of delicious greens before finishing its life cycle.
Biennial Behavior
- Flowers in second year after winter vernalization
- Produces seeds before dying in zones 8-10
- Maintains edible leaves throughout dormancy period
Annual Adaptation
- Completes full lifecycle in one season below zone 6
- Bolts quickly during summer heat waves
- Produces seeds before first hard frost
Overwintering Capacity
- Survives down to 15°F with proper protection
- Regrows from intact root crowns in spring
- Requires mulch and row covers in zones 5-7
Expand productivity with strategic overwintering. In zones 6-7, put down 6 inches of straw mulch before the first hard frost. Cover plants with vented row covers. I have overwintered chard for three years using this technique, and they are very vigorous in the spring and during the first harvest. They can produce your early-season greens when other greens are not available.
Recognize the bolting signals that the plant lifecycle has completed. Plants will produce tall flower stalks with small green flowers. The leaves will become bitter and tough. At this point, allow some plants to produce seeds if you want to have seeds to plant again next season. During this time, can collect seeds when the flower heads are brown and dry.
Maximize harvests through succession planting! Start new seeds every 3 weeks from early spring (even if your plants have differing lifecycles). I utilize 3 grow-out intervals: spring established biennials, summer established annuals, and fall established overwinter candidates. This allows me to harvest without fail throughout the year!
Read the full article: How to Grow Swiss Chard Successfully
