Growing Plants From Seed For Summer Pots & Containers

By Harriet Rycroft

Sowing the seeds of success – Easy and effective seed-grown plants for summer containers.

I am a bit of a skinflint when it comes to plants. Don’t get me wrong, I am indeed a certified plantaholic, but I do like to get value for money, so any plant I buy is likely to have cutting material lopped off it, or to be split into pieces as soon as it gets through my garden gate.

When I worked at Whichford Pottery I prided myself on planting lots of pots for very little money. By my tenth year in the job I worked out that I was spending an average of one pound per pot per year on plants.

If you’ve seen my planting style then you know that I like my pots to overflow, and many of the pots were very big, so how was this possible?

Well, I re-used all perennial plants (hardy and tender) and propagated them, but my displays would be very boring with the same plants every year – and that’s where seeds come in.

2 Planting dominated by Zea mays ‘Quadricolor’ and Nemesia ‘KLM’

If you grow from seed you can grow spectacular plants which LOOK expensive, and you can use them generously. One £2 seed packet can give you anything up to a couple of thousand seedlings, at prices like this you can afford to experiment.

I mix my seed-grown plants with cheap bedding, summer bulbs, favourite cuttings-raised plants, and a few rarer perennials, looking for pleasing combinations of colour, texture and form

3 Germinating seeds – the most exciting part of gardening

Of course a heated greenhouse and a thermostatically-controlled heated bench or propagator is a real advantage. On a smaller scale however, you can germinate seeds in plastic bags on your windowsill, so there is no excuse not to have a go!

There are plenty of guides online and in books, and there really is nothing more magical in gardening than seeing those first tiny green specks sprout from the compost. Just a handful of packets of seed can transform your displays.

Here’s a list of a few of the more willing growers, plants which can be packed into your pots in different combinations every year.

You may already be using some of them in your flower beds, but they can look extra special in pots. Most are annuals, some are perennials, but all of them will look good in their first summer:

Agastache ‘Liquorice Blue’

Agastache ‘Liquorice Blue’

Spikes of blue flowers, and aromatic foliage. In a sunny place this will make the bees go berserk.

Centaurea cyanus (Cornflower)

Centaurea cyanus (Cornflower)

An unmistakable bright blue, other colours are available, including soft pinks (as in ‘Classic Romantic’) and the wonderful dark red ‘Black Ball’.

Cerinthe major ‘Purpurascens’

4 Cerinthe major ‘Purpurascens’

I guarantee people will ask you about this odd plant with glaucous blue-grey leaves, iridescent blue bracts and purple flowers. Bees love it too.

Cineraria maritima ‘SilverDust’

Cineraria 'Silver Dust'

Useful, finely cut, downy grey foliage; a great foil for bright and pastel colours alike. I like the slightly less common ‘Cirrus’ too.

Cosmos ‘Sensation’, ‘Double Click Snow Puff’, ‘Sweet Sixteen’ – there are lots of good varieties of Cosmos. The tallest ones are best in really big pots but their foliage doesn’t cast much shade so you can cram them among other plants. They take about five minutes to germinate.

Didiscus caeruleus ‘Madonna Mix’

6 Didiscus caeruleus ‘Madonna Mix’

Almost unbearably pretty umbels in white, pastel blue and pink. Hoverflies love them.

Helianthus annuus- Good old sunflowers – they don’t have to be monsters, choose compact varieties like ‘Pacino’ or ‘Teddy Bear’.

Hordeum jubatum 

7 Hordeum jubatum brings soft texture and movement to any planting

The seedlings will look like weeds at first but in late summer you will get graceful pink-tinged barley heads, which are fabulous backlit.

Other grasses to look out for include Bunny’s tails (Lagurus ovatus), Agrostis nebulosa and Stipa tenuissima.

Lobelia erinus - Available as plug plants but cheaper as seed and dead easy to grow. Look out for dark blue ‘Monsoon’, pink, white and blue ‘String of Pearls’, ‘Riviera Sky Blue’ and many more.

Tropaeolum majus (nasturtium)

8 Tropaeolum majus ‘Alaska Mix’ beneath Dahlia ‘Red Riding Hood’, lighting a shady corner

These are very handy trailing or semi-trailing plants and can do surprisingly well in part shade. I find the most useful are those with handsome foliage such as ‘Empress of India’ (red flowers and blueish leaves) or ‘Alaska’ (variegated).


9 Nemesia ‘Masquerade’

I grow these in the same way as Lobelia, sowing a small pinch of seed in modules (small cells) and potting up the tiny plants in small clumps rather than individually.

My favourites are ‘KLM’ (blue and white), ‘St George’ (red and white) and ‘Masquerade’ (yellow and purple, crowned with crazy white prongs).

Some packets will advise you only to sow direct outside in the spring or autumn but I sow everything, even hardy annuals, in trays or modules indoors during late Feb to late April.

I find a temperature of about 16C germinates almost everything – read instructions and get a second opinion online if you are any doubt. Even if you have a packet which fails completely it isn’t a big loss. But be warned, a few seedy successes will have you hooked!

10 Container jungles – more achievable than you might think.

If you have a greenhouse, a propagator and nice big containers you can try larger, more exotic creatures like Ricinus ‘New Zealand Giant’ or Zea mays ‘Quadricolor’ (pink, white and green striped ornamental sweetcorn), or the banana-like Ensete ventricosum.

Soon you will be scouring the most recherché seed catalogues and growing mini jungles in your pots!

And I haven’t even got started on all the climbers and edible plants that you can easily grow from seed…

PHOTOGRAPHS – COPYRIGHT HARRIET RYCROFT – all plantings by Harriet Rycroft, created at Whichford Pottery, Warwickshire.

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