Start Tubers and Bulbs

Save Money Starting Tubers and Bulbs Indoors in Winter

I love using summer blooming tropicals and tender perennials in my annual containers and plantings. But the nursery plants are SO expensive and not easy to save and store for the next season. So instead, I order the tubers to start over winter. There a just a few things you need to know to make your efforts successful.

First, most tubers and bulbs as well as some roots need a chilling period. Each plant requires a different amount of time but generally they need to stay chilled a minimum of 11 weeks, some need as much as 17 weeks, to mimic their natural “winter” cool season. So you won’t be able to start them too early, as a matter of fact you won’t even find them in your nursery or available to ship until the have completed their minimum chilling period. In some areas that will be as early as December but for many they may not be shipped until spring. From some nurseries they just assume you will plant them in the ground and wait well into your growing for them to grow and bloom. I am not that patient. So when ordering tubers and bulbs, be sure to determine when they will ship if you want to start them early indoors.

I have also learned the hard way that some of the tropical tubers and bulbs, for instance caladium, need VERY warm conditions to sprout. I was able to have them shipped fairly early for a very early start. I expected a sunny window on top of a radiator would be enough but apparently not. Absolutely nothing happened and and I planted them in my containers with no hope of seeing caladiums. By the time it got good and hot outside in July, guess what peaked out among the other annuals? The black oxalis also popped up about then. I believe they would have sprouted and grown to bedding plant size if I had a heat mat to keep the heat consistent. Once sprouted they do grow fairly quickly, but if you want nice size plants to transfer when the weather is warm enough, start as early as you can.

Most tubers and bulbs as well as perennial root stock will want warm moist conditions but not wet soil or with their pots sitting in water. You can grow them in a terrarium or create a makeshift terrarium to keep them warm and moist. Most bulbs will want to be planted at a depth twice their diameter. Fill your pots half way, place the bulb or tuber, and add appropriate amount of soil and lightly tamp. Some times it is hard to tell what is top and what is bottom so check any directions that came with your purchase. usually their is a flat and or “hairy” bottom and a pointed nodule top. Tubers should have a hairy bottom or little knobs of root nodules. Place all the pots in a drip tray. You can cover them with plastic if you like and if you have a heat mat they will love that.

There are quite a few tropicals and tender perennials that you can start easily over winter. Don’t forget to label your pots if you are sprouting more than one variety! Yes, you will forget which are which.

Tuberous Begonia - start at least 8 weeks before your average last spring frost, 14 weeks if you can if you want to get a little plant growth. These tubers have a bit of a depression on top and rounds out full on the bottom. Cover with up to only one inch of potting soil 70 degrees or warmer is ideal. Be sure the weather will stay fairly warm before hardening off outdoors.

Caladium - these slowpokes will take at least 6 weeks just to sprout under the soil and really needs a very warm spot. Growth will be very slow initially. 75 to 80 degrees will be necessary. The top of these tubers has knobby bud eyes that will be the plant sprouts.

Calla Lily - seems like the more beautiful the plant, the more finicky they are. Calla Lily will sprout in 6 to 8 weeks under and inch or two of potting soil. Then give them time in a sunny spot or grow lights after the foliage finally appears. Introduce them to the outdoors very slowly, starting with a shady spot and expose them a little at a time to sunshine.

Canna - Canna are big and they need a bigger pot than the rest right from the beginning. Plant the rhizomes 3 or 4 inches deep. Give them at least six weeks just to sprout.

Dahlia - Beautiful Dahlias are a bit finicky. Use large well drained pots but only cover with an inch of potting soil. The crown needs to be exposed out of the soil. Don’t over water, dahlia tend to rot. Plan on 8 to 10 weeks to get a small plant to move outdoors.. Don’t get anxious to get them outside, they hate cool soil.

Elephant’s Ear - Planted an inch or two deep, Elephant Ear may be ready to transplant in about 8 weeks, but usually are a bit slow.

Gladiolus - starting glads can be done in pots and soil, or in water. The corms should be placed in a shallow dish with about a 1/4 inch of water. Place them in a bright spot for about 4 weeks to sprout before planting. If you are able to start your gladiolus early enough to get several inches growth, they should be planted deep when you move them outside. They do grow quickly so you may get a good sized plant to bury. Place the corm 5 inches deep in the soil covering foliage to that depth.

Oriental and Asiatic Lilies - Certainly you can start these indoors, but they do grow fast so you don’t need to start too early. However they are so widely available, affordable, and hardy that you can plant your bulbs outdoors in the fall or spring or just buy bedding plants.

If you plan to save and store your bulbs I would keep a chart of when you plant everythng, when they sprout and when a small plant stage is reached. Then next year you can tweek your schedule if necessary. But any head start you get by at least letting the tubers sprout before planting time will produce blooms for you quicker. The longer sprout and growth time you can give them, the faster they will grow full and bloom once out in warm weather.

If you have a reliable nursery that provides top quality bulbs and tubers they will typically have the plants that are most successful in your area. For more variety there are wonderful reputable suppliers you can try. I like Van Bourgondien, Eden Brothers, and American Meadows. The challenge is finding a supplier who will ship in fall or winter. I was able to get mine shipped in winter from Michigan Bulb, or save yours next season!