Cornflower 'Blue Boy' - Kew Flowerhouse Seed CollectionCentaurea cyanusBlue-Bottle, Bachelor's Buttons

Sow cornflower seeds outdoors where they are to grow from March to April. Choose a position in full sun on well drained soil which has been raked to a fine tilth. Sow seeds thinly, at a depth of 3mm (1/8") in drills spaced 30cm (12") apart. Water the ground regularly, especially during dry periods. Germination usually takes 14-21days. When cornflower seedlings are large enough to handle, thin them out to 15cm (6") apart.

Alternatively, grow cornflowers indoors from August to September for early summer flowering next year. Sow cornflowers on the surface of a good quality seed compost at a temperature of 18-23C (65-73F) and cover with a very fine sprinkling of compost or vermiculite. Do not exclude light as this helps germination. When seedlings are large enough to handle, transplant and grow them on in cooler conditions until large enough to move outdoors. Overwinter cornflowers plants in cool, light, frost-free conditions before planting out the following spring, or growing on as greenhouse pot plants.

Seeds and garden supplies will normally be delivered within the time period stated against each product as detailed above. Plants, bulbs, corms, tubers, shrubs, trees, potatoes, etc. are delivered at the appropriate time for planting or potting on. Delivery times will be stated on the product page above, or in your order acknowledgement page and email.

Orders for packets of seed incur a delivery charge of £2.99.

Orders which include any other products will incur a delivery charge of £6.99.

Where an order includes both packets of seeds and other products, a maximum delivery charge of £7.99 will apply - regardless of the number of items ordered.

Large items may incur a higher delivery charge - this will be displayed in your shopping basket.

Please see our Delivery page for further details, and more information on different charges that may apply to certain destinations.

For more information on how we send your plants please visit our Helpful Guide on plant sizes.

Thompson & Morgan strives to ensure that all its plants are delivered to you in the perfect condition for planting. While the majority of our nursery plants cope well with slight delays in intransit, sadly, the time it takes to deliver to certain locations in the UK means that we can't guarantee this for some of our smaller plug products and tender bedding and vegetable lines, which do not respond well to the extra journey time. So regretfully while we offer the majority of our live plant offering nationwide, we are unable to ship plugs, begging plants and tender vegetable plants to the following areas: HS, IV41-IV49, IV51, IV55-56, KW15-KW17, PA34, PA41-48, PA60-PA78, PA80, PH40-PH44, TR21-TR24, ZE1-ZE3