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As the weather warms up, I’m itching to start growing again and it’s tempting to start as soon as possible but there are good reasons for sowing a bit later in the year. I’m going to focus on sowing under cover, as this is the method I use for the majority of my annual flower seed. The other option is direct sowing where you sow straight into the soil outside but you must wait for the soil to warm up for this.

Sowing under cover means that you gain a head-start and will get earlier flowers. You don't need a greenhouse or potting shed for this. I use my windowsills and using 2 windowsills, I have space for all the annuals that I grow. By having my seedlings in the house, I can keep an eye on them so that I don't forget to water them and turn the pots each day. You can also protect your seedlings from being munched by slugs and other pests, until they are larger - larger plants are more able to withstand a bit of nibbling.

Sowing flower seeds
Sowing annual flower seeds

Common questions

Q. When should I sow my annual flower seed? - (every packet seems to have slightly different timings!)

A. When it comes to sowing, day-length is more important than warmth. If you sow too early, your seedlings are likely to become leggy from straining for the light by the time you plant them out.

The first thing to do is to split the annuals you want to grow into hardy* and half-hardy** types to simplify things. Then, sow all the hardy seed from early - mid March and all the half-hardy ones from early April. You can also sow at any time throughout the spring and summer so if you miss sowing in March and April, you can still have flowers this season, they’ll just appear later.

As long as there is time for them to grow and flower before the first frost, you can sow annuals at any time. I sow a 2nd batch of hardy annuals when my first batch start flowering, so that once the first batch have flowered for 2-3 months, I have plants to replace them with. Using this method, I have a continual supply of flowers from late May until the first frosts.

*Hardy annuals are just that, hardy - meaning that they’ll survive winter cold and wet and withstand a frost.

**Half-hardy annuals cannot withstand frosts and so need to be planted out after all risk of a frost has passed. This is generally mid-late May in this area, so if I sow at the beginning of April, I know that my plants will be the perfect size for planting out when the warmer weather arrives.

Sweet peas
Sweet peas

Hardy annuals can also be sown in late August - October for early flowering the following year. They go into a semi-dormant state through the winter, coming into growth again in the spring. Sweet peas, Cornflowers and Ammi all do well with this method.

Q. Do I need special seed compost?

A. Seed compost is specially formulated for growing seeds but for me, a good multi-purpose compost is less expensive and performs just as well. Trials have shown that multi-purpose can be really good and the good ones had less peat than the top rated seed compost in a recent Which? trial. Peat-free options generally performed less well but they are being improved all the time. Whichever compost you use, break up any large lumps and fill your seed trays or pots loosely to the top before firming  it down gently – the bottom of another tray/pot can be used to press it down. Leave a small gap at the top for watering.

Q. How deep do I sow the seed?

A. Seeds vary in size, generally, larger ones like sweet peas should be buried under about an inch of compost and smaller ones just need a fine sprinkling of compost over the top. Very fine ones like poppies can be left on the surface.

Cornflower
Cornflower 'Black Ball' (hardy-annual)

Q. Should I use trays or pots?

A. Seed trays can be useful for small seeds where you want to sow a lot of one type of seed. However, I find that I don't want to grow more than 3 or 4 of each type of annual in my cutting beds so to make things as simple as possible, I sow all my seed directly into square black plastic 9cm pots. This is the ideal size to house seedlings for up to 6-8 weeks, without getting root-bound, which is a good size for planting out and prevents the time-consuming need to prick them out and pot them on.

I plant 2-3 seeds per pot (or a small pinch of very tiny seeds) and pull out all but the strongest seedling once they emerge). 8 of this size pot fits nicely into a square seed tray that acts as a reservoir for water. The tray fits perfectly on to my windowsills and means the whole tray can be easily turned every day to prevent seedlings growing towards the light. I also happen to collect large numbers of this size of pot as it’s a popular size for garden perennials to be housed in when you buy them from the garden centre. At Miles Garden Design, we are left with lots of this size pot left at the end of a planting job so, for me, they are essentially free - lucky me! You may be able to get them for free on sites like Freecycle or you can buy them fairly cheaply on the internet. You can re-use them, making sure that you clean them thoroughly at the end of each year.

Vintage flowers

Q. How often should I water my seedlings?

A. Water the compost well before you sow the seeds, rather than after sowing, so that you don’t dislodge the seeds or wash off the covering of soil. Check pots daily and water sparingly with tepid tap water. Don't use water from a rain barrel as it may harbour diseases and small seedlings are vulnerable. Use a small watering can with a fine rose. Keep pots moist but not wet.

Cutting garden bed
Annual flowers

Other seed sowing tips

Labeling. Label all your individual pots or seed trays as it is very easy to lose track of what you have sown. I use sturdy multi-coloured plant labels and use a black wax pencil to mark them. At the end of the season, you can scrub off the writing with a sponge scourer and some washing up liquid and re-use them. I like using coloured ones as you can use a different colour for different plants in each tray so you can immediately see how many of each type you have. Plus, they look pretty.

Create a list, use fresh seed. Have a plan for planting up your annual cutting bed and a list, so you know exactly how many of each plant you need to sow. I generally only grow 3/4 of each type of annual and actually don’t need much seed from a packet. Spare seed can be shared with friends or stored for using the following year but do check expiry dates on packets as the germination rate does go down, the older the seed is. If you are unsure, you can perform a simple test to see if the seed is still viable.

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News from the Cutting Garden

Well, the school summer holidays are upon us and so this will be my final post to the website for a while. I will be turning my attention to entertaining my hyperactive 3-year-old daughter Rosie and attempting to lure my 7-year-old Ben away from his computer games.

I've been cutting flowers from the garden practically every day for the last few weeks. My early hardy annuals are producing buckets of blooms. I've been leaving quite a lot of flowers for the insects but ensuring that I always deadhead when the flowers are over to ensure that the plants keep on producing. I've had plenty of flowers so that I can have a display in almost every room of the house and still had some spare to create some lovely little jam jar posies as presents for teachers at the end of term.

Jam jar posies make excellent and indiv
Jam jar posies make excellent and individual presents for teachers at the end of term

Mysterious plant deaths

I've just planted out a second batch of hardy annuals - a few more Cornflowers and some Ammi and Bupleurum to replace those that died off last month in mysterious circumstances. I thought I had the answer last week when I dug up a Cornflower that had been merrily flowering away but had gone yellow and floppy looking. Under the plant, I found what I initially thought to be a Vine Weevil grub, but soon realised was too big. After a lot of searching images of disgusting white grubs on the internet, I think it was actually a Swift Moth Caterpillar. These live in the soil and nibble on plant roots which may explain the Cornflower death. I didn't find any of these caterpillars when digging up other plants that had failed and they seemed to die off earlier so I think either another pest or fungal disease is probably at work there. I'm hoping that everything else will survive and we don't have too many more die-offs.

Annuals from the cutting garden
Sweet peas, Scabious, Cornflowers, Alchemilla, Gypsophila, Cosmos, Lemon balm, Lupins

Annuals

I'm currently picking Cornflowers, Sweet Peas, Lupins, Larkspur, Malope trifida, Gypsophila, Panicum grass, some lovely Nigella (Love in a Mist) and the odd early Cosmos flower.
Annuals that will take over from these as the main crops in a few weeks will be Zinnias, Scabious, Cosmos, Didiscus (Blue Lace Flower), Salvias, Coreopsis, Carnations, and Chrysanthemum 'Polar Star'.

Malope trifida 'Vulcan'
Malope trifida 'Vulcan', Pelargonium 'Lord Bute', Cornflowers, Lupins, Lemon balm

Perennials

Elsewhere in the garden borders, I am harvesting Lavender, Knautia macedonica, Verbena bonariensis, Perennial Scabious, Francoa sonchifolia, Oregano (now flowering), White and Pink Mallow, Sanguisorba, Persicaria, a few Dahlias that have just started blooming in their pots, Pelargonium 'Lord Bute', Galega officinalis and the first Fennel flowers.

Jobs to do

Aside from picking flowers (not really a chore!), I check my raised beds every day or two and spend 5-10 minutes on the following: deadheading, fishing out the odd weed, tying in new growth to supports, squashing aphids and replacing the odd plant that has reached the end of its life or has succumbed to the mystery disease with a seedling from the potting shed. I also try to give the raised beds a really good watering once a week and have fed the Sweet Peas and Dahlias with flower food every few weeks.

Raised Bed
Hardy annuals in my raised cutting bed. Amberboa, Malope, Cornflowers, Lupins, Larkspur and Cornflowers

What's next?

Well, I'll just keep picking my flowers from the raised beds and perennial borders and will look forward to the later flowering plants coming into bloom. I'll clear away spent plants when they cease to flower and put them on the compost heap. I'll keep on top of the jobs listed above - a little time spent every few days will do the trick.

I'll report back on progress after the summer - hope to see you then. In the meantime, I'll still share my cut flower pictures on Facebook and Twitter and have also been working on producing some Cut Flower Guides detailing everything you need to know about growing, cutting and arranging individual flowers such as Sweet Peas and Cornflowers.

Flowers from the cutting garden in July
July cut flowers - Cosmos, Larkspur, Cornflower, Sanguisorba, Galega officinalis, Mallow, Amberboa and Gypsophila
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It's hard to narrow it down to just 10 but these are my favourite annuals to grow for cut flowers. It's important to choose a balance of colours, flower shapes and foliage when deciding which annuals to grow in your patch.

Zinnias, Sunflowers and Scabious
Zinnia 'Giant Dahlia mix', Sunflower 'Vanilla Ice', white Scabious 'Tall Double Mix', Cosmos 'Purity' & Cornflower (that's 5 of my top ten in one vase!)
  1. Ammi majus, Bishop's flower - a delicate, creamy-white umbellifer similar to Cow Parsley with attractive fern-like foliage. It's a great filler to add frothy bulk to an arrangement and to set off other flowers. Flowers from mid-Summer to mid-Autumn.
  2. Cornflowers, Centaurea cyanus - Brings a relaxed, naturalistic feel to a vase. This lovely native flower used to grow in abundance on arable land. The deep blue flowers are easy to grow and can be sown in Autumn for early flowering next Spring. As well as classic blue, I recommend 'Black Ball', a dark, red wine colour. Flowers from early Summer if sown in Spring.
  3. Scabious, Scabiosa atropurpurea - Prolific flowerers from early Summer until the Autumn frosts. The flowers are long-lasting and are a great plant to grow as they also look attractive at the bud stage and at the seed head stage. Let some flowers go to seed to take advantage of this. I grow 'Tall Double Mix' which has a mix of pinks, whites and crimsons but I also like the dark red 'Black Cat' variety and 'Ping Pong' has blue flowers and amazing sculptural seed heads.
  4. Larkspur, Consolida ajacis - Useful tall spires of flowers to add height to your vases. It's similar to a Delphinium but smaller with more delicate foliage and flowers more prolifically.  I'm growing 'Stock flowered mix' this year which has a blend of colours ranging from light pink to dark purple. Flowers in late Spring from an Autumn sowing or early Summer from a Spring sowing.
  5. Love in a Mist, Nigella damascena - A classic cottage-garden flower with lovely fennel-like foliage. It has gorgeous seed pods which can be used later in the season. I grow it scattered throughout my perennial borders where it self-seeds into any gaps. 'Miss Jekyll' is a classic blue, 'Persian Rose' is a delicate pink.

    Zinnia bud
    Zinnia bud
  6. Cosmos, Cosmos bipinnatus - Very easy to grow and produce hundreds of flowers. There are a range of pinks and crimsons to pure white forms. Flowers from mid-Summer to the first frosts. I grow 'Purity' for its simple white flower which adds elegance to a vase and, for something a little different this year, I'm trying 'Click Cranberries' which has more layers of petals with raggedy edges and a deep red colour.
  7. Euphorbia oblongata, Eggleaf spurge - like Ammi, this is invaluable to grow as a filler for your arrangements. Bright, greeny-yellow flowers offset darker flowers beautifully. As with all Euphorbias, the sap is a skin irritant so wear gloves when harvesting.
  8. Zinnias, Zinnia elegans - These natives of Mexico come in a range of rich, bright cheerful colours and will flower from late Summer to mid-Autumn. I've grown 'Giant Dahlia' mix in the past which produces a mix of colourful flowers but this year I'm trying 'Yoga' and 'Art Deco'. The lime-green 'Envy' is a little temperamental to grow and I haven't found that it has flourished as well as some of the other varieties.
  9. Sunflower, Helianthus annuus, H. debilis - Bright, cheerful flowers that are easy to grow and loved by children. Big flower heads look great on their own in a jug but they can be hard to combine with other flowers. I grow Helianthus debilis 'Vanilla Ice' (hard not to sing 'Ice, Ice baby' every time I think of this one!) which produces an abundance of smaller pale yellow flowers that combine beautifully with other blooms. Flower from Mid-Summer to Autumn.
  10. Sweet peas, Lathyrus odoratus. The individual flowers may not last long once cut but these climbing annuals produce so many flowers over a long period and have some of the best scent of any flower. They come in so many colours, you are spoilt for choice. I go for ones that smell as good as they look such as 'Matucana'. Flower from late Spring into Autumn.
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