Growing Chrysanthemums – Greenhouse Chrysanthemums in Summer
The Summer Standing Ground
During early June, the chrysanthemum plants are removed from the cold frames – by which time they should be well-hardened off – and are placed in a specially prepared area for the summer. By this time of the year they will all be in their final pots. I sometimes place mine outside round about early May, but I stand the plants close together and protect them from frost and wind with straw bales or polythene screens.
An area – usually at the side of a greenhouse – can be prepared by covering the ground with a 2 to 3 in. layer of industrial ashes. Alternatively, slates or tiles can be used for standing the pots on. These materials prevent worms from entering the pots, disturbing the root systems and blocking the. If a special area is not available, the pots can be placed along the side of a path.
On the standing ground the pots are placed in double rows, allowing 18 in. each way between the plants, and about 3 ft. between each double row. At the end of each row, insert a stout wooden stake about 4 ft. in height. Then stretch a wire along each row securing it at the top of each stake. Canes about 4 ft. in length should have been inserted in each pot after the final potting, so the tips of these are then tied securely to the wires to prevent the plants from being blown over during high winds.
I mentioned that if young chrysanthemum plants were grown in boxes they could be planted out in the open ground for the summer For the amateur who wants just a fewfor cutting it is the simplest way of growing them. It cuts out the need for constant watering of pots, and the fear of the pots drying out, so causing poor growth. These plants will provide really good flowers for cutting and plenty of them. The varieties Loveliness and Favourite respond particularly well to this method of cultivation.
Thefor these should be prepared as for the outdoor-flowering chrysanthemums They may then be planted 18in. apart each way in double rows with about 3 ft. between the double rows.
Watering Chrysanthemum Plants
During the summer, in hot weather, chrysanthemum plants may need watering two or three times a day. The best method of finding out whether clay pots need watering is to tap them with a cotton reel on the end of a cane. If the pots ‘ring’ then they need watering, but if there is a dull thud then this is an indication that they contain sufficient water. With plastic pots we cannot tell by tapping them, so we must be guided by the appearance of the top of the soil. When using plastic pots it is necessary to be more careful with watering as they do not dry out so quickly as clays, and therefore there is a greater tendency to over-water them. Spraying the plants overhead with clear water each day in the early morning will help in the production of shoots.
As the chrysanthemum plants are potted finally into John Innes No. 2 Potting Compost – which is fairly rich – they will not need much feeding for a number of weeks. However, some feeding may be carried out from early August, about once a fortnight, and then gradually stepped up to once a week until the colours of the petals begin to show, when it should cease. Use either a soluble or liquid general-purpose fertiliser or sprinkle a dry general-purpose fertiliser around each plant and water it well in. Choose one with a fairly high potash content. Proprietary chrysanthemum fertilisers are available.
If any of the plants appear to be making soft rather than hard growth which can be determined by the texture of the leaves then a watering of oz. Of sulphate of potash dissolved in 1 gallon of water will help to harden the plants and improve the quality of the flowers.
If necessary this can be done from early June to the middle of July. Some varieties do not need a second stopping, so it is best to consult a chrysanthemum catalogue which should indicate the number of stops required. As I mentioned, this task is best learned through experience so keep accurate records of the stopping dates of each variety. At this stage the first crown buds should have formed so the second stopping merely involves pinching these out to obtain the second crown buds which will produce the flowers. Further stopping is usually unnecessary for most varieties, unless very late flowers are required.
This involves the removal of surplus side shoots which appear from the leaf axils down the whole length of the stem. These should be nipped out when about 1 to 1-1/2 in. long, starting from the end of August through to October. Any shoots which appear around the base of the stem should also be removed.
I described the technique of disbudding early-flowering chrysanthemums, and the same principles apply to greenhouse varieties. It is usual to make a start in early August, especially with large exhibition varieties, and to carry on into early October when the Decoratives and Singles are disbudded.