Palms
Fresh seeds and high temperatures, up to 35ºC (95ºF), are usually needed to encourage germination. However, an easier way is to mix seeds with moist peat and place them in a strong, clear, polythene bag. Seal the bag and put it in a warm, shaded greenhouse, perhaps under the staging. When roots and leaves appear, transfer the seedlings into individual pots.
What is germination?
To most gardeners, germination is when young shoots appear above the surface of the soil in the garden or compost in seed-trays (flats) and pots in greenhouses. Technically, however, germination is when the embryo within a seed breaks into growth, initiating the development of shoots and roots. The requirements for germination – moisture, air and warmth, together with the influence of light – are described on page 9.
SOWING VERY FINE SEEDS
Fine, dust-like seeds, such as those of Begonia and Meconopsis, are difficult to see and handle; although you can just press them onto the surface of the compost, often it is better to mix them with dry silver sand and then sow them. Here are a few clues to success when sowing fine seeds:
• Select a dry, shallow pot, about 13 cm (5 in) wide, and fill it with soil-based seed compost (this has a finer texture than peat-based types and forms a flatter surface for fine seeds).
• Firm the compost evenly with your fingers, then refill and level it with the pot’s surface. Use a round compost presser (or the top of a jar) to level the surface about 12 mm (½ in) below the rim.
• Open the seed packet and add a heaped teaspoon of silver sand to the packet. Close the packet and shake to ensure the contents are well mixed.
• Some gardeners sow seeds directly from the packet, but unless you are experienced at this it is likely that all of the seeds will fall out in a heap.
• Instead, tip the mixture of seeds and silver sand into a piece of white, stiff, paper or card – about 15 cm (6 in) long and 6 cm (2½ in) wide – that has been folded into a V-shape along its length. Then you can easily see the mixture of seeds and silver sand, and by directing the folded paper over the compost and tapping its end you can encourage the seeds to fall over the surface evenly.
• There is no need to cover the seeds; just use a presser, or the top of a jar, to press them into the compost.
• Stand the pot in a bowl shallowly filled with water; when moisture seeps to the surface of the compost, remove the pot and allow it to drain. Then, either cover it with a transparent lid or place the pot in a polythene bag and seal it.
• Remove the bag as soon as seedlings appear.
Hardy annuals in borders
Is there a wide range?
There are many hardy annuals to grow in gardens (see opposite page). You simply sow the seeds where they will germinate, grow and flower, either in borders totally dedicated to annuals or as fillers in established herbaceous or mixed borders. When growing them in dedicated borders, sow the seeds in groups of differing final plant sizes, so that they dovetail with each other and drench the bed or border in inexpensive colour throughout summer.
WHEN SHOULD I SOW THEM?
It is a waste of seeds and time to sow hardy annuals too early in spring, when the soil is still cold and wet; the seeds will not germinate and may even decay before conditions are right for germination.
Here are a few clues to sowing hardy annuals:
• The earliest time for sowing seeds depends on the weather, and even within a distance of a hundred miles the optimum time may vary by seven to ten days – sometimes more. If you are in doubt about a suitable time, your local gardening club will be able to help.
• Gardens on warm, sun-facing slopes can be sown earlier than those with a cold and wind-blown aspect.
• While waiting for the soil to warm up and dry out slightly, avoid walking on it and causing compaction.
• Wait until the soil’s surface is dry and crumbly – usually during mid- and late spring.
HOW TO SOW HARDY ANNUALS IN BORDERS
1 Dig the soil in winter and in mid-spring use a wooden rake (or large metal type) to level the surface and to remove large stones.
2 To evenly firm the soil, systematically shuffle sideways over the entire area. Then, use a rake to remove the foot marks and to re-level the surface.
3 When the surface is level, use a pointed stick to mark individual sowing areas. Make them of differing sizes. An alternative method is to use sharp sand to define the sowing areas. Make corner areas large and dominant.
4 Within each sowing area, form 12 mm (½ in) deep drills about 20 cm (8 in) apart. If possible, form the drills in each sowing area at different angles to the ones next to it. This helps to prevent the entire bed appearing too regimented. There are two ways to form the drills: using a draw hoe (above left) and with a pointed stick guided by another stick (above right). Using a straight stick for guidance is ideal when sowing a small area.
5 Sow seeds evenly and thinly in the base of each drill. Label each sowing area with the name of the annual, together with the date.
6 Use the flat top of a metal rake to push and pull friable soil over the seeds. Then, employ the top of the rake again to tap down and firm soil over the drills.
7 When sowing is complete, lightly but thoroughly water the entire area without disturbing the seeds (use an upturned fine rose). Then, to prevent birds disturbing the surface, lay twiggy sticks over the area. As soon as seeds germinate, remove the twiggy sticks or lines of cotton.
8 When the seedlings are large enough to handle, carefully thin them without unduly disturbing the soil and loosening the roots of the remaining seedlings. Put the seedlings that are removed on a compost heap; do not leave them on the soil’s surface. Then, lightly but thoroughly water the whole area.
ANNUALS TO SOW IN THIS WAY
The range of hardy annuals that can be sown in borders each year is extremely wide, and all of the following plants are described in the ‘A–Z of propagating plants’ (see pages 42–78):
• Agrostemma githago ‘Milas’ (Corn Cockle)
• Amaranthus caudatus (Love-lies-Bleeding)