How To Perfectly Repot Pond Plants: A Step-By-Step Guide

Pond plants not only bring natural beauty to your garden, they have added benefits including improving water quality, offering shade, absorbing excess nutrients, and providing a habitat for local wildlife. But like all plants, they require a bit of maintenance every so often.

Spring and early summer are ideal for repotting your pond plants. Whether you've bought new plants or your existing ones are overgrowing their baskets, swapping for larger pots allows your plants to thrive, keeping your pond healthy in return. But where do you start with repotting, and how can you have the most success with your pond plants?

Why do I need to repot plants?

Most pond plants are sold in small nursery pots that are unsuitable for the long term. As your plants mature and grow, they will require more space for root development and access to fresh nutrients. Without occasional repotting, these plants can easily become root-bound, stunting their growth. You may also find your water quality degrades due to soil leaching into the pond water. This can cloud your water and clog your filter.

What you'll need

To successfully repot your pond plants, you will need a selection of tools and materials listed below.

Tip: Try our Swell Planting Basket Bundle Set to get you started.

Planting baskets

Use large baskets with mesh sides to allow water flow, ideally ones specifically designed for pond use. Choose the size based on the type of plant you are repotting:

• 22-23cm: ideal for most marginal plants (irises, reeds, flowering marginals)
• 40cm or more: suitable for large lilies or established root masses
• Contour basket: fits on narrow shelves

Explore our range of planting baskets for all pond sizes.

Hessian or planting liners

Hessian is used to line the basket, keeping compost securely inside whilst letting water and roots pass through. These pieces of material also prevent loose soil from getting into your pond, clouding your water, and clogging your filter.

Aquatic compost

This compost has been specifically formulated to be low in nutrients and fertiliser free, preventing excessive algae growth. It is not recommended to use garden soil or multipurpose composts, as they are too rich in nutrients. This may cause instability in your pH levels as well as algae blooms.

Coarse gravel or pebbles

Gravel or pebbles are used as a top layer to anchor your plant and to prevent compost spilling out into the water. Wildlife will also be less able to dig in the soil and uproot your plant.

Check out our selection of pond plant soil and gravel for pond-safe options.

Sharp scissors or a knife

Ideal for making clean cuts to roots and leaves, and for cutting away excess hessian.

Repotting your plants: Step-by-step

1. Remove the old pot: Gently remove the plant from the pot. If the plant has become rootbound, you may need to break it open.
2. Trim the roots: Cut back any long roots so that they can sit vertically to stimulate new growth. Remove any dead or rotted leaves and roots. 
3. Line your basket: Use 2 layers of hessian or a planting liner and line the base and sides. Make sure the entire inside of the basket is lined to keep compost inside and support the plant as it grows.
4. Add aquatic compost: Fill the bottom third of the basket with aquatic compost, pressing it down slightly.
5. Position the plant: Place the plant upright in the centre of the basket. Fill the gaps at the sides with the compost and press down gently to eliminate any air pockets.
6. Top with gravel or pebbles: Add around 2-5cm of gravel or pebbles over the top of the compost to stop soil being washed out.
7. Trim the edges: Cut off any excess hessian for a neater finish, and then slowly lower the basket into position.

Dividing established plants

Larger pond plants can become overcrowded as they mature. This is especially common for some iris and water lily species, reducing their flowering and impacting their health. It is generally recommended to divide the plants every two to three years to help encourage new growth, and prevent them from taking over the pond.

To divide your plants, use a sharp knife or spade to cut the root ball into as many sections as required, depending on size. Make sure each section has a healthy amount of roots and foliage to allow for continued growth. After you have cut the root ball, pot each segment using the method above. 

Early spring is the best time to divide your plants, right at the start of the growing season, allowing them plenty of time to establish.

Feeding and aftercare

Fertilising your pond plants is an important step in keeping them healthy. Only use pond safe fertilisers throughout the growing season, dosing as instructed. Typically, tablet fertilisers are applied once per season by pushing them into the compost, and liquid fertilisers are used monthly. Feeding is important for plants that require higher nutrient levels like lotuses and lilies.

Frequently asked questions:

Why is my plant floating up or falling over?

This is often caused by the basket being too small or top heavy. Replant in a larger basket, making sure it is weighted with gravel to fix this.

How deep should I place my plants?

This depends on the species you are keeping. Most marginal plants need shallow shelves of around 15-25cm, whilst lilies prefer deep placements of 30-60cm.

When should I repot my plants?

Late spring or early summer is the best time to repot. Avoid winter when plants are dormant, as frost may damage exposed roots.

Where can I get the materials needed for repotting plants?

At Swell UK, we have a range of products perfect for repotting your plants. Check out our pond planting accessories for top rated products at low prices.