Why Grow Nasturtiums in Pots?
Cultivating nasturtiums in pots offers a fantastic way to introduce vivid colour and edible blossoms to patios, balconies, or small gardens. These cheerful plants, known for their bright, trumpet-shaped flowers and peppery leaves, thrive exceptionally well in containers, often performing even better than when planted in the ground. The primary challenge when growing nasturtiums in pots is ensuring they receive adequate light, water, and nutrients without becoming waterlogged or overcrowded. Fortunately, these adaptable plants are relatively forgiving, making them a rewarding choice for gardeners of all skill levels seeking to add a splash of cheerful colour and culinary interest to their outdoor spaces.
- Pots allow nasturtiums to be placed for optimal sunlight.
- Container growing makes pest monitoring more focused.
- Edible flowers and leaves add culinary interest.
- Success depends on pot size, soil, and watering.
The appeal of nasturtiums lies not only in their visual impact but also their versatility. Their trailing or climbing habits, depending on the variety, mean they can spill over edges, soften harsh lines, or create a vertical display. Furthermore, both the flowers and leaves possess a mild, peppery flavour, making them a popular addition to salads and garnishes. Growing them in pots means you can easily position them where they'll be most enjoyed, both aesthetically and culinarily, and move them if conditions change, such as during unexpected weather shifts.
However, not all pot-grown nasturtiums will flourish without attention. Over-fertilising, poor drainage, or insufficient light are common pitfalls that lead to leggy growth with few flowers. Understanding the specific needs of these plants when confined to a pot is key to unlocking their full potential. This guide explores the solutions to common problems and offers advice to ensure your container nasturtiums are a visual and gastronomic delight throughout the season.
Choosing the Right Pot and Soil
What makes a good home for your nasturtiums in pots? The container itself is the first crucial decision. Nasturtiums prefer slightly restricted root conditions, so avoid excessively large pots, which can lead to overwatering and root rot. A pot with a diameter of around 20-30 cm (8-12 inches) is typically sufficient for a single plant or a small cluster, depending on the variety. Ensure the pot has ample drainage holes; this is non-negotiable. Terracotta pots are a popular choice as they are porous and allow the soil to breathe, but they can dry out more quickly. Plastic or glazed ceramic pots retain moisture better, which might be preferable in hotter climates or for those who tend to underwater. For trailing varieties, consider wider, shallower containers to allow them to cascade effectively.
The soil mix is equally vital. Nasturtiums are not heavy feeders and actually perform best in soil that is not overly rich. A good quality, general-purpose potting compost is a suitable base, but it should be amended to improve drainage. Adding perlite or grit to your compost can create a lighter, airier mix that prevents waterlogging. Aim for a pH level that is slightly acidic to neutral, around 6.0 to 7.0. Avoid composts that are too high in nutrients or manure, as this can encourage lush foliage at the expense of flowers. If you are using soil from your garden, sterilise it first to remove any potential pests or diseases, and mix it thoroughly with grit or perlite.
Soil Mix Alternatives
- Standard Potting Compost: A reliable, ready-made option.
- Compost + Perlite/Grit: Enhances drainage for plants prone to root issues. Use a ratio of roughly 3 parts compost to 1 part perlite or grit.
- John Innes No. 2: A loam-based compost providing good structure and moderate nutrient levels, often favoured by experienced gardeners.
When planting, fill your chosen pot with the prepared soil mix, leaving a few centimetres at the top for watering. Gently remove the nasturtium seedling or plant from its nursery pot, taking care not to disturb the roots too much. If the roots are tightly bound, you can gently tease them apart. Place the plant in the pot at the same depth it was growing previously, and firm the soil gently around the base. Water thoroughly after planting to help settle the soil and reduce transplant shock. For climbing varieties, consider adding a small bamboo cane or a simple trellis at planting time to support their future growth.
The single most important factor for successful nasturtiums in pots is excellent drainage.
Watering, Feeding, and Light Requirements
How much water do your potted nasturtiums need? Consistency is key. Water thoroughly when the top inch of soil feels dry to the touch. Overwatering is a common mistake, leading to yellowing leaves and root rot, especially in pots with inadequate drainage. Conversely, underwatering will cause the plants to wilt, and may lead to flower drop. The frequency of watering will depend on the weather, the pot material, and the size of the plant. On hot, sunny days, you may need to water daily, while cooler, overcast conditions require less frequent attention. Always check the soil moisture before watering.
Feeding for container-grown nasturtiums should be approached with restraint. These plants are not demanding and can become leggy and flower poorly if fed too much. A general-purpose liquid feed, diluted to half strength, can be applied sparingly once every 4-6 weeks during the main growing season, but only if the plant shows signs of nutrient deficiency (such as pale leaves). If you've used a good quality potting compost, you may find that additional feeding is unnecessary. In fact, slightly lean soil conditions often encourage more prolific flowering. If you're growing nasturtiums for their edible flowers and leaves, it's advisable to use organic fertilisers or to avoid feeding altogether if your compost is already nutrient-rich.
Light for Nasturtiums
Nasturtiums are sun-lovers. For the best flowering, they require at least 6-8 hours of direct sunlight per day. Insufficient light will result in weak, straggly growth and a noticeable reduction in the number of blooms. While they can tolerate partial shade, flowering will be significantly diminished. Place your pots in the sunniest spot available on your balcony or patio. If your location experiences extremely hot summers, some afternoon shade can prevent the plants from becoming stressed, but ensure they still receive ample morning sun. The vibrant colours of nasturtiums are at their most spectacular when bathed in bright sunlight.
Prevent common issues by ensuring your pots are never left standing in saucers full of water; empty any excess water after about 30 minutes to allow roots to breathe.
A sunny position is paramount for abundant nasturtium blooms in pots.
Troubleshooting and Ongoing Care
Even with the best intentions, problems can arise when growing nasturtiums in pots. One frequent issue is the appearance of aphids. These small, sap-sucking insects often congregate on the undersides of leaves and on new growth. A strong jet of water from a hose can dislodge them, or you can use an insecticidal soap, ensuring it is safe for edible plants if you intend to consume the leaves or flowers. Regular inspection is key to catching infestations early. Another common problem is the development of fungal diseases, such as downy mildew, particularly in humid conditions or when plants are overcrowded. Good air circulation, proper watering techniques (avoiding wetting foliage), and choosing disease-resistant varieties can help mitigate this risk.
Pruning and deadheading are less critical for nasturtiums than for some other flowering plants, as they tend to be self-cleaning to a degree. However, removing any yellowing or dead leaves promptly will keep the plant looking tidy and help prevent disease. If a plant becomes particularly leggy or overgrown, a light trim can encourage bushier growth and more flowers. For trailing varieties, you might want to prune them back occasionally to maintain their shape and prevent them from becoming too sparse.
When to Take Cuttings
While nasturtiums are typically grown from seed each year, you can extend their season or propagate new plants by taking cuttings. The best time to take cuttings is usually in late spring or early summer, before the plant becomes too woody. Select a healthy, non-flowering shoot that is about 7-10 cm long. Using a clean, sharp knife or secateurs, cut just below a leaf node. Remove the lower leaves and insert the cutting into a pot filled with a moist, well-draining seed compost or a mix of peat and grit. Cover with a plastic bag or place in a propagator to maintain humidity. Keep in a bright spot, out of direct sun, and they should root within 3-4 weeks.
When comparing soil needs for nasturtiums in pots, prioritise drainage over nutrient richness.
Growing cosmos in pots or cultivating sunflowers alongside them can offer a rich tapestry of colours and textures, and nasturtiums are excellent companions. They deter some common pests like aphids and whiteflies from more sensitive plants, and their bright blooms complement many other summer flowers. Consider companion planting nasturtiums with herbs like rosemary or basil, or even with vegetables like tomatoes or cucumbers. Their peppery foliage can deter certain pests, while their trailing habit can help suppress weeds around the base of larger plants.