Your guide to The Three Sisters planting method

Whether you’re a seasoned grower or an allotment beginner, this technique is a simple way to maximise space and enjoy healthy crops. Lucy Hutchings of Shegrowsveg explains more…

The Three Sisters planting technique is a time-honoured method of companion planting, originating from Indigenous agricultural practices in North America. This method involves growing three crops; corn, beans and squash, together in a symbiotic relationship. Each of these plants supports the others in unique ways, creating a sustainable and productive growing environment. This technique is well-suited for home growers in the UK, providing a rich, biodiverse garden space.
Here’s all you need to know about The Three Sisters planting method and how to do it in your garden…

Why use The Three Sisters planting method
Each plant in this companion planting system serves multiple purposes. Tall, sturdy corn stalks act as natural trellises for the climbing beans. The beans, in turn, fix nitrogen in the soil, benefiting all three crops. Meanwhile, large squash leaves spread across the ground, creating a living mulch that retains soil moisture and suppresses weed growth while their prickly stems deter pests.

Planning Your Three Sisters Garden
To successfully grow the Three Sisters, gardeners need a sunny space of at least 3x3 metres. While smaller spaces can work, this size allows for proper spacing and maximum yields. The plot should receive at least 6-8 hours of direct sunlight daily and have well-draining, fertile soil.

Planting Guide
Step 1: Start with corn
1. Begin when soil temperatures reach 15°C consistently, and create mounds approximately 1.2 metres apart. Each mound should be about 10 centimetres high and 40 centimetres wide.
2. Plant 4-5 corn seeds per mound, 3 centimetres deep.
3. Wait until corn reaches 15 centimetres in height before the next step

Step 2: Add the beans
Choose pole bean varieties rather than bush beans.
1. Plant 3-4 bean seeds around each corn stalk. Position seeds about 15 centimetres away from the corn, and plant at 2.5 centimetres depth.

Step 3: Introduce the squash

1. Sow 2 squash seeds between the corn mounds when bean seedlings emerge.
Plant at 2.5 centimetres depth, and consider both winter and summer squash options based on your climate.

Common problems with The Three Sisters method
Timing: The most frequent challenge gardeners face is timing. If beans are planted too early, they can overwhelm young corn stalks. If planted too late, they might not reach their full potential before the season ends. Following the height guideline for corn (15 centimetres) helps avoid these issues.
Spacing: Proper spacing prevents competition between plants. While it might seem like wasted space initially, the mature plants will fill in quickly. Overcrowded plants lead to reduced yields and increased disease risk.
Variety selection: Always choose appropriate varieties:
Corn: Select sturdy, tall varieties that reach at least 2 metres. Choose a shorter-season variety suitable for the UK climate, such as ‘Stowell’s Evergreen‘ or ‘Golden Bantam‘.
Beans: Climbing varieties like ‘Carminat‘ or ‘Monte Gusto‘ are ideal.
Squash: Smaller varieties like ‘Baby Boo‘ or ‘Kamo Kamo‘ are easier to manage in limited space.

Tips to ensure The Three Sisters method is a success

- Prepare soil well with plenty of organic matter
- Install wind breaks in exposed gardens to protect tall corn
- Water deeply but infrequently to encourage strong root growth
- Consider adding flowering companions like marigolds to attract pollinators
- Monitor for signs of nutrient deficiency, especially in the corn

Planning for harvest
Expect a succession of harvests throughout the season - beans will typically be ready first for regular picking, summer squash provides ongoing harvests and corn and winter squash mature later in the season.
Try to leave some dried beans on the vine for next year’s seed.

The Three Sisters method offers an efficient and sustainable way to grow three nutritious crops in a single space. While it requires careful planning and timing, the rewards of this time-tested planting system make it well worth the effort for home gardeners looking to maximize their growing space while honoring traditional agricultural wisdom.

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