Start with a modest selection whose purposes are distinct: stock or snapdragons for upright lines in the cool season, celosia and zinnias for summer shape and colour, dahlias for prominent flowers, plus mint or grasses for texture. Select varieties marketed specifically for cutting. After keeping one season’s records of health, first flowering, stem length and performance in water, you can broaden the collection deliberately.

It cannot be relied upon throughout Ireland. An unheated structure may lengthen the useful periods in autumn and spring, but it supplies neither winter warmth nor additional daylight. Success with winter flowers varies with the immediate site, outside weather, natural light, the building and the selected plants. Unless winter production has been planned horticulturally and technically, regard a cold house mainly as a means of extending the ordinary season.

The answer changes with the plant, available daylight, temperature and the intended picking period. For quick summer flowers, several modest batches generally work better than one heavy sowing. Avoid applying the same weekly gap automatically. Schedule another batch once the earlier plants are growing securely and you can anticipate when the bed will again offer enough light, room and time for the work involved.

Put tall production flowers with substantial roots into beds; reserve tables for young plants, compact pots and hygienic cutting supplies. Combining both is especially effective: provide two accessible growing beds, an uncluttered propagation surface, and a permanent position at the edge for buckets and brief conditioning work.

Crowding and persistent humidity are particularly troublesome for zinnias. Increase the distance between plants, improve circulation, irrigate at bed level rather than wetting leaves, and discard badly affected tissue. Limit excessive nitrogen, and examine moisture around the roots before adding water. Also look beneath foliage for insects and start ventilation promptly when sunshine warms the house.