Who hasn’t admired the view of a flower box-adorned Mediterranean street whilst on holiday? Many urban areas are adding foliage to their buildings, balconies and roof gardens, helping them remain cooler in hot weather and providing a welcome burst of colour to passers-by.
Window box planters offer home and business owners an opportunity to display their green fingers to a world outside their windows and are a wonderful way to bring joy and colour to everybody’s daily life.
Window planters provide a beautiful focal point both inside and outside the house. This article will guide you through the plants that can survive outdoors and those you need to cosset indoors! I’ve included plans to make your own wooden window planter, ideas for how to fill it and what to plant in each season, as well as a brief history of community window planter boxes. Let’s start with that.
Community window boxes
The therapeutic benefits of growing plants are well documented. The innovative ‘Veg Your Ledge‘ community initiative in Forth, Scotland, has given local residents the opportunity to grow their own produce on their window sills. They receive a free upcycled window sill planter compost, vegetable seeds and bags of information and encouragement.
Plans to help you build a window sill planter box
Grow your own
If you’re keen to grow your own produce or flowers from your window sill, you’ll need to consider a few things first:
- Shade or sun? Consider if the planter box will be in the shade or full sunlight. Wonderful exotic plants like orchids will thrive on a warm windowsill but will shrivel up if the nighttime temperature drops significantly.
- Soil. You will also need to check that the type of soil you fill your planter box with will provide the right mix for all the plants you want to add. One way to do this is to provide different layers within the box. You can place a small plant into a brick or pot then fill the area with soil to cover the pot, this allows other plants to take advantage of the deeper or different soil.
- Season. Is this planter box for summer only? You are spoiled for choice with all the beautiful annual summer blooms available. However, when the cooler autumn air arrives, you will need to remove annuals that have reached the end of their lives then add perennial or evergreen plants, which will provide foliage and colour all year round. Read on for more details.
Seasonal window sill planter boxes
Here are some suggestions for what to plant each season so your window sill box is always filled with life.
The trick with an indoor window planter box is to make sure most plants have separate pots which you can place into the planter, then remove after they flower.
Amaryllis will provide one spectacular bloom each year but needs warmth all year round. Allow it to dry out completely after flowering, then remove the whole pot for its dormant phase once the flower has died back.
Hyacinths are a fantastic choice for planter boxes because the scent of their gorgeous flower head remains for weeks in the room where they are placed. These need to germinate in darkness so cover the pot and transplant them into your window sill when the first bud appears. Once they have flowered, you can leave them in the planter box and they should continue to flower year after year.
Cyclamen offer delicate flowers from December to spring.
Busy Lizzie is an old favourite of mine, a flower loved in cottage gardens for centuries. Easy to propagate, they enjoy being in a warm sunny place and a window box is perfect. Just make sure you prune your busy Lizzie if it starts to get leggy or overshadow other plants.
- You can have a range of hardy flowers, from delicate white snowdrops, blue grape hyacinths, and yellow crocuses to golden, yellow daffodils that announce spring has sprung!
- Plant these bulbs late in the autumn to get them settled. You need to allow the foliage to live for a month or so after flowering to allow the bulbs to gain strength for the next year’s growth. Then cut the stems back for the summer flowers. Leave them in the soil in your planter box and add some fresh compost.
- Tulips will flower from April onwards providing cut blooms for your living room.
- Primroses are another flower which blooms in both spring and autumn, offering vivid yellow flowers and clumps of leaves. Their cousin, polyanthus, offers a range of colours too.
Any plants which can be moved outdoors for summer will reward you with abundant growth and I recommend this. The plants below all need summer sunshine and will grow well indoors.
- Herbs are wonderful indoors in all seasons and basil will happily live on your window sill all year round.
- Succulents like Aloe Vera, which are a bit too delicate for the UK outdoors, can add a green splash to your indoor window box. If placed in a sunny position, many of them will flower.
- Spider plants are superstar indoor plants. Easy to grow and care for, they’ll appreciate time outdoors in the summer months.
- Dwarf tomatoes are another delight, producing dozens of fruits and perfect for younger gardeners.
There are plenty of shade loving indoor plants too so don’t despair if your window sill is not so bright.
- Ferns are gorgeous indoors and it is really fascinating to watch them uncurl their new leaves.
- Sansevieria, the snake plant or mother-in-law’s tongue is fine with some indirect light. Its spiky, yellow leaves with green edging can be sharp so be careful if you have children and pets.
- Summer savoury is a herb that enjoys semi-shade and it has a winter relative, winter savoury, which can be picked when the summer variety has died back.
Cover up your spring bulbs with fresh compost and get ready for abundant foliage and flowers! It’s a good time to add a dahlia or a sedum to your window box, which will flower later in the year.
- Geraniums grow really well in planter boxes, as do petunias.
- Lavender brings aromatic scents to your window box which you will smell incredible as you walk by.
- Nasturtiums always look wonderful with their fiery orange and yellow flowers, the leaves and flowers are edible too.
- Try adding edible plants like tomatoes, herbs and small vegetables. These produce beautiful flowers, like the purple blooms of an aubergine.
- Herbs like thyme have fragrant flowers which attract pollinators and they will live on through every season too.
As the evenings draw in and the temperature cools, it’s time to start moving delicate plants indoors.
- Tarragon must be moved indoors early in September before the weather changes. Carefully dig out its roots and take cuttings too, just in case. Make space for it in your window sill planter and enjoy its fragrant leaves in cooking all winter long.
- Herbs like parsley can come indoors now too but leave sage, rosemary and thyme outdoors as they’ll survive whatever the winter throws at them.
- Geraniums need to be kept warm over the winter so remove any dead flowers and leaves and check for pests. Water them well, add a fresh layer of compost and place them in a sunny window sill planter.
- By autumn, many of the summer bloomers are still colourful, you can enjoy the gorgeous flowers of dahlias now if you planted them in time.
- Autumn plants like sedums provide wonderful late nectar for butterflies and you will have many peacocks and red admirals visiting if your sedums are in bloom.
- Sometimes the spring primroses will flower again because the heat of the summer sun has gone.
- You can plant tulips now, ready to flower April.
Window sills are not the most hospitable of environments in winter. Indoor plants have to contend with heating and outdoor plants may become frozen. You can protect some plants by covering them up if extreme weather is forecast.
Bubble wrap, old blankets and even cling film may save delicate window-box perennials.
- What can beat a winter poinsettia planter box? The red leaves will brighten up any room and if you take care of it, it may even last another season.
- At this time of the year, many flowers will bloom indoors, such as cyclamens, Christmas cactus and the cape gooseberry plant.
- Pansies and cyclamens will struggle through the beginning of the winter and will flower again the following year but this can be a grim season for flowers.
- If you planted some forsythia earlier in the year, you will be comforted by its spikes of yellow blooms now. Cut the plant back to the end of the flower stake to keep its shape, right after flowering.
- Winter jasmine provides a gorgeous scent and you can even cut these for flower arrangements.
- Holly bushes are producing red berries now too and these are perfect in flower arrangements and wreaths. They will need a lot of space in your window box and spread very easily so keep them pruned and enjoy the foliage all year round
Before you buy a new window sill planter box, see if you can find one here:
- Your local authority. Search for advice and information from your local council to see if similar schemes to Forth community veg boxes are being offered. Some authorities offer discounted compost bins and water butts so there is no harm in asking.
- Ask relatives and experienced gardeners if they have any extra planter boxes you could use on your window sill or have a look in your local charity shop.
- Examine your child’s toy box or your plastic recycling and see if there is anything you could re-model into a DIY window sill planter. Some old children’s toys can be easily transformed.
- Do you live in a flat with a balcony? Funding is available to encourage communities to become more aware of the benefits of growing food and recycling waste. Many gardening centres, like Dobbies, offer small grants to community groups to encourage them to get gardening. Chat to your neighbours and start a gardening group, or join your local horticultural society. See places to help with funding in the links below.