Choosing the right varieties to suit your production style is always a challenge. Take the time to select the right combination of early and late finishers. Based on your previous experience growing various cultivars, you’ll be able to label each cultivar as tall-, medium- or short-growing, which will facilitate PGR applications appropriate for the vigour of the plant.
Timing and Scheduling
Timing and scheduling of plant production is dependent on many factors. Night temperatures, day length, planting dates as well as pinching dates should all be taken into account when planning your production schedule. This is a good time to remind yourself about the phenomenon of “heat delay”. Although beyond your control for the most part, as it is due to excessively high night temperatures, be aware that it can delay flowering beyond the expected flowering dates.
Early Plant Care
Anything that interferes with the optimal growth of cuttings may force the plants into a flowering stage (i.e., bud formation). To prevent such premature budding, cuttings must be kept actively growing. Immediately after planting, provide the cuttings with optimum moisture and fertility levels. Supplying adequate moisture and fertilizer will assist in keeping the plants in a vegetative growth phase. Heavy nitrogen fertilization will help plants grow past undesirable crown buds.
Transition from Greenhouse to Outdoors
Monitor the weather closely when deciding to move garden mums from a controlled greenhouse environment to the unpredictable outdoors. The earlier you move the plants, the higher the risk of night temperatures falling to the 50°F mark, which can cause premature budding. A prolonged period of cool temperatures can also start the flowering process.
Well-mounded and well-proportioned plants develop with adequate spacing. Plants that are grown too close together can develop weak stems, yellowing of lower leaves and a stovepipe shape.
With many other crops, one method of height control is to maintain low moisture levels in the media. I do not recommend this with garden mums, since we know that frequent moisture stress on young plants will promote crown bud development. With garden mums, focus on fertilizer selection and PGRs to control height.
Hardy mums respond favourably to higher rates of fertilizer, particularly nitrogen. The more you feed, the more vegetative growth you will have and the bigger the plants will be. This is good to know, since a fertility program for garden mums should be designed based on the desired plant growth in order to produce full, strong plants. If plants are grown too lush, this growth habit will produce tall, weak plants with stems that break off easily. During early vegetative growth, do not shy away from feed, however when the plants have reached two thirds of the desired height and head size, it is a good time to switch to a toning fertilizer.
Soil Moisture levels
If your objective is to produce large quality garden mums, you will have to maintain adequate moisture levels in the containers at all times. Regardless of the media you select, good water management practices should be part of your overall production plan! Outdoor mums may be subject to cool wet periods followed by hot, dry conditions as the summer progresses. If plants are allowed to dry out too frequently, they will experience considerable stress and smaller, harder plants of lesser quality will prevail. Older plants can also become prone to pythium infection if they are allowed to wilt repeatedly due to inadequate moisture.
Reducing the Incidence of Disease
Regardless of what method of irrigation is used, foliage should be dry going into the evening to prevent bacterial leaf spot, botrytis, septoria and alternaria, as well other foliar diseases. Besides foliar pathogens, Fusarium oxysporum has been identified as a major problem among hardy mums. This fungus spreads via the root system. Good drainage with minimal puddling of water throughout the growing area helps to reduce the spread of this disease.