Hardy Annuals from Seed
Hardy annuals can be sown during spring outside in the open ground in the positions in which they are to flower. However, having gardened from East Anglia northwards and regularly encountered the vagaries of our climate north of the home counties I would suggest that for most gardens a late spring sowing is more prudent, except on heavy clay soil in the north where an early summer sowing would be more acceptable. Little is gained by sowing seed early in cold uncompromising clay soil. Seeds sown under such conditions usually rot before they have had an opportunity to germinate. Use the calendar as a guide to sowing, but be influenced more in your decisions by soil and weather conditions.
The success of hardy annuals sown directly outside owes as much to autumn soil preparation as to the skill of the gardener sowing the seed during the spring. A deeply cultivated soil with plenty of organic matter incorporated into it, and one that has been weathered over winter should be ideal. This will retain moisture during dry periods and if well weathered, will knock down with the hoe into a good friable medium that will be ready for seed sowing immediately. Indeed, the final preparation of soil that has been weathered should be left until just prior to sowing. Early tilth preparation will result in soil compaction if it rains before you have an opportunity to get the seeds in.
However, it is important that the soil is firm prior to sowing. Shuffle across the bed, drawing one foot up to the other as you go. One passage across the bed or border should be sufficient. After that create a shallow tilth with a rake. It is useful to apply any fertilizer at this stage. I prefer a simple balanced fertilizer like Growmore which comes in a granular form and can be distributed evenly over the surface of the soil prior to raking in. Always apply fertilizers to the manufacturer’s instructions and never scatter them amongst seedlings and young plants or else severe leaf scorching will occur, especially if the weather is hot and dry.
When a border or bed is to be used exclusively for annuals, rather than the annuals merely used to fill in gaps in the mixed border, it is best to mark out the sites of individual varieties with a sprinkling of sand. Groups of an irregular shape and size always present the best visual effect. While taller varieties are usually better towards the back of the border, strict placement according to height is undesirable. The seeds of annuals are generally covered with about their own depth of soil, small seeds being carefully broadcast over their designated area and then raked in. The broadcasting of seed means the even distribution of seed by hand, using the eye as a judge as to the correct density and spread. Very fine seeds that are difficult to distribute evenly should be mixed with a little dry silver sand. This enables you to see the exact spread of the seed, assuming that the seed is equally distributed throughout the sand. Large seeds, like those of the nasturtium, require sowing individually in their final positions.
Newly sown seed and emerging seedlings must be carefully watched, especially during dry periods, and water must be given as necessary to ensure unchecked growth. Crowded seedlings should be thinned at the earliest opportunity if damping-off disease is to be avoided and strong healthy plants are to develop. Damping-off disease is characterized by black patches which appear at the base of the stems of seedlings at the point where they emerge from the soil. This basal rotting causes the seedlings to collapse.
Rarely are single plants affected, the disease being extremely virulent and causing considerable losses, especially during warm humid weather. Watering regularly with a product that has benomyl as the active ingredient will exercise some control. Alternatively the copper-based material, popularly referred to as Cheshunt compound can be used. This is available in a powdered form which is mixed with water and watered on to the seedlings every ten days or so. It is wise to use one of these materials as a preventative against damping off disease in any event.
Some annuals resent root disturbance, but many can be successfully moved in their seedling stage to another part of the garden. This is useful as it presents the opportunity of utilizing the seedlings thinned from main concentrations elsewhere. As most annual seedlings grow very quickly it is important to provide some kind of support early on. Brushwood is ideal and should be incorporated at the seedling stage in order to restrict root damage from the probing ends of the sticks. By staking early the young plants can grow through their twiggy support and disguise them quite naturally.
Seedling annuals are susceptible to slug damage, so it is prudent to scatter slug pellets amongst them at the same time as the stakes are being erected. Annuals of the Crucifer family, such as candytuft and Virginian stocks, are vulnerable to the attacks of flea beetles which make tiny holes in the seed leaves and turns them a pale sickly yellow-green, distorting the first true leaves as well. Attacks are most likely during dry weather, but a generous dusting with derris will help effect a control. To prevent a build-up of this pest in your garden, be sure to remove host weeds like charlock and shepherd’s purse at the first opportunity.
