Optional if the ground doesn’t freeze. Mildew will attack some varieties in the late summer and into the fall. Then, the tubers have time to harden-off and remain strong in winter storage. If they freeze, they will rot and if they are kept too warm, they will shrivel. Plants prefer moist but not soggy soil, and adding a layer of mulch around plants will help the soil retain its moisture. Always check your fertilizer labels for nitrogen amounts when buying fertilizers for dahlias. The dirt is a friend to Dahlia Tubers. Grow dahlias in a sunny garden spot on loose, well-draining soil that's amended with organic matter. Heavy blooms from large-flowered cultivars may bow these leggy stems. Dahlias love to be in the dirt. Ground should be warm and well drained at planting. Ideal temperatures for winter tuber storage are 7-10 C (45-50 F) with a humidity between 65-75%. We do not recommend watering until sprouts are at least 4” – 6” inches above the ground. Her writing Be sure to remove old blooms from your plant to keep it growing and blooming all season! The tubers will send up more growth, but the frost damage will delay the time to maturity and, therefore, delay the onset of flowers. Gently lift the Tubers with a spade or digging fork. It’s better to feed them too little, then too much. Sanitize a knife, garden shears or other cutting tool with a solution that's at least 70 percent ethanol or isopropyl alcohol. Although growing dahlias may require a little more attention than growing other types of plants, die-hard fans of these lovely flowers know that the payoff is worth a little extra care. papers, horticultural articles, and magazine and newspaper columns. Some will have grown bigger than others (this is normal); each variety is a unique plant and has its own characteristics. Space plants between 45-60cm (1.5-2ft) apart. Some years, there will be more pests than others—this is Nature. Unfortunately, this combination doesn't exist in most gardens, but native soil can be amended to maximize its effectiveness. Also, it encourages new blooms and better bloom color throughout the season. You can divide tubers in the fall or in the spring. Using raised beds and large containers (at least 15 inches in diameter), both of which generally have better drainage than in-ground soil, is another strategy to keep the tubers from sitting in waterlogged soil. Do not water your tubers after planting—wait until the sprouts appear, unless you are in extremely hot and dry conditions in which case you may water them immediately. Remember, the dahlia is really a tropical plant, so when frost hits them, it kills them instantly. To be on the safe side, you can start the tubers in pots indoors and transplant them a week or two after the last frost. If you try to squeeze the tubers into a pot that's too narrow, you may damage the eye at one end of the tuber, which is where the stem will sprout. You can love them to death! Tubers dug before a frost may be “green” and shrivel badly or rot in winter storage. Bulbs such as lilies, daffodils, and tulips can be planted in wet, cold soils in the fall. Most spray programs should begin before you see a problem, preferably the end of June thru August. Dahlias need a sunny location to thrive. Lay the tuber horizontally at a planting depth of 4”-6” inches and about 18” to 24” inches apart, then cover with soil. These can be found as vegetable fertilizers at your local garden centers. Sprinkle cornmeal or diatomaceous earth around your plants to control slugs. Dahlias are herbaceous perennials in U.S. Department of Agriculture plant hardiness zones 7 through 10, but gardeners in zones outside this perennial range can grow them as annuals. Keep soil moist but not soggy and fertilize each month during the growing season with 8-8-8 fertilizer. Dahlias should be sprayed in July and August for powdery mildew. Otherwise, the rain will generally be enough. Dahlia Tubers can be planted from Mid-April until Early June, depending on your location and your climate. Use aged steer manure, compost, or a 10-10-10 fertilizer spread evenly over the bed, then till it in. If you skip the mulch, you may have to water your plants twice a week during hot, dry intervals. To mitigate the risk to tubers, gardeners in the coldest zones of dahlia's hardiness range may want to dig them in fall and overwinter them indoors. Prepare your beds a few weeks before planting. During dry, hot weather dahlias should be given a deep watering at least twice a week. Dahlias have roots near the surface. If you have a heavier soil, work in sand or peat moss to lighten the texture of the soil for better drainage. Herbicide will kill your dahlias! Apply fertilizer monthly—beginning when sprouts appear and continuing once a month until the end of August. Either way is fine. If you have a clump of tubers, spread out all the tubers attached to the dormant stem like spokes on a wheel before placing in the planting hole. For a quicker start, plan the tubers 3” to 4” inches deep and then “hill up” soil after plants are up and growing. Pinching will give you a shorter/bushier plant and if you choose to pinch them back, it should be done when plants are just under 60cm (2ft) tall.