Selecting the Right Size Pot for Small Gardens

19th September 2024

Selecting the right pot size for your plants is crucial for their health and growth. Whether you're starting with seedlings or working with established plants, understanding the needs of your plants and the characteristics of different pots can make a significant difference in their development.

This guide covers essential considerations for choosing the appropriate pot size based on plant size, root system, and growth habits. We’ll explore how to match pots to different types of plants, the importance of pot-to-plant ratio, and tips for repotting and maintaining plant care. With the right potting strategy, you can ensure your plants thrive and grow beautifully.

Here are some key factors to help determine the correct size plant for your pot.

Plant Size and Root System

• Seedlings and small plants: For new plants, choose a pot that is about 2.5-5 cm larger in diameter than the root ball or current pot. The roots should have room to grow but not so much that the soil stays too wet and promotes root rot.
• Mature plants: For established plants, aim for a pot that is 5-10 cm wider in diameter than the plant's current root spread.
• Fast-growing plants: If the plant grows quickly, opt for a pot that allows for at least 2.5-5 cm of root growth per year.

Type of Plant

• Deep-rooted plants: Choose deeper pots for plants with long roots (e.g., tomatoes, carrots, or some shrubs).
• Shallow-rooted plants: For plants like herbs or groundcovers, a shallower pot can be sufficient, as their root systems don’t require much depth.
• Cacti and succulents: These plants generally prefer shallow, wide pots since they have more spreading roots rather than deep roots.
• Trees: If planting trees as a feature, opt for a large pot no smaller than 65-70 cm in diameter. We recommend starting with a large, mature tree so that the impact is immediate and the tree has already had some structural shaping.
• Hedging: When planting hedging for privacy, remember that pot depth will contribute to plant height. Choose pots with a depth of at least 50 cm, with deeper pots providing more height at planting time.

Growth Habit

• Sprawling or bushy plants: Plants that grow outward rather than upward (like herbs or some perennials) benefit from a wider pot to provide stability and space for root expansion.
• Tall, slender plants: These might need a narrower but deeper pot to support their vertical growth.

Pot-to-Plant Ratio

• A good rule of thumb is that the pot should be no more than 1/3 larger than the root ball. Too much soil without roots can retain excess moisture, leading to root rot or poor plant health. The exception is when using large pots with multiple plants for a layered look. More plants in the pot will allow their roots to absorb more water, reducing the risk of root rot. Using a high-quality, fast-draining potting mix will also protect your plants.

Repotting

• When repotting, you generally want to move up one pot size at a time (usually 5 cm wider and deeper than the current pot).
• If you notice roots circling the bottom of the pot or growing out of the drainage holes, it’s time to move to a larger pot.
• When using very large planters, it won’t be possible to repot once the plants become established. Therefore, start with a high-quality potting mix and top-dress with organic compost, fertilizer, and mulch 3-4 times during the growing season. Liquid feeding with organics every month will also maintain a healthy, bioactive potting mix.

Plant Care Requirements

• Moisture-loving plants: Plants that need consistent moisture may benefit from a slightly larger pot because it retains water longer.
• Drought-tolerant plants: Plants like succulents, which prefer to dry out between waterings, may do better in a smaller pot to avoid excess water retention.

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