When to Plant Flower Bulbs
Flower bulbs bloom throughout the spring, summer, and fall for vibrant, low-maintenance color throughout the garden. They are either planted in the spring or fall months. Spring-planted flower bulbs prefer warm growing conditions and typically bloom throughout the summer and fall months. Wait until after your last spring frost date to plant bulbs such as Calla Lily, Begonia, Dahlia, Gladiolus, etc.
Fall-planted flower bulbs require a cold period of 12-16 weeks (35-45 F) to set flowers. In warmer climates, this cold period can also be created by storing your bulbs in a refrigerator for the necessary time before planting. This can be helpful when purchasing bulbs after the planting time for your growing location or when planting them indoors. You may sometimes see bulbs sold as “pre-cooled,” meaning they have already been stored for the required cooling time and are ready to plant upon delivery. Fall-planted bulbs such as Tulips, Daffodils, Hyacinths, Crocus, and Alliums typically bloom in the spring, often before other spring and summer flowers start to emerge.
How to Plant Bulbs
Generally, bulbs should be planted at a depth of 2-3 times as deep as they are tall. Place in the soil with the pointed end up and cover. Utilizing a bulb planting tool or hori hori can make quick work of planting at the appropriate depths.
Mistakes to Avoid
The most common mistakes made when planting bulbs include planting at the wrong depth, planting in the wrong season, watering incorrectly, overcrowding, and growing in poor soils. You can find the recommended planting depth, distance, and planting seasons on each bulb page. When planting we recommend always amending your soil with compost for a little boost of nutrients. If you have heavy clay soil, you may want to amend it with sand, perlite, or vermiculite for improved drainage. Check out the bulb care instructions below for more info on bulb growing conditions.
Spring Flower Bulbs
Bulbs
Bulbs are plant structures that form layers around a central shoot. These layers store nutrients that support growth and flowering. When growing bulbs it is more important to feed or fertilize your crops in the fall months rather than the spring, as this is when the bulbs are taking up nutrients to store for use the following year. Bulbs are typically round with a papery protective layer.
Many people prefer growing bulbs for their perennial habits and low-maintenance care. When planning your gardens be sure to include a few bulbs for reliable pops of color throughout the spring, summer, and fall months. Want some color indoors too? No problem! Many bulbs, including paperwhites, amaryllis, and hyacinths can easily be grown indoors for a touch of nature.
How to Care for Bulbs
- Sunlight: Bulbs typically need 6+ hours of sunlight. However, many spring bulbs can be grown under deciduous tree lines as their leaves may not develop until after your spring bulbs bloom. Plan your growing location according to your bulb's blooming season.
- Water: Always water after planting your bulbs, but be careful not to overly saturate the area when planting in the fall, as the ground is anticipated to freeze. In the spring and summer months, plan for about 1 inch per week, including natural rainfall. If you experience wet springs you likely won’t need to apply additional water much, if at all.
- Soil: Plant into well-draining soil rich in organic matter. We recommend mixing in some compost before planting for added nutrients and improved soil quality.
- Mulch: Spreading mulch around your planting bed is helpful to reduce weeds by cutting off any weed seeds sitting in your soil from light. Intensely weeding around bulbs may lead to some being pulled up or disturbed later in the season.
Growing Bulbs in Containers
Flower bulbs can grow very well in containers. Just be sure to select a container size that will accommodate your bulb selection. Larger pots are best to help insulate the bulbs or allow them to be moved to a protected area during the winter months. Keep in mind container plantings will require more frequent watering throughout the season. The larger the container, the more water your soil will be able to retain. We recommend planting containers with a high water retention soil mix.
How to Overwinter Bulbs
Overwintering is simple. Simply allow the foliage to die back naturally. For spreading bulbs like irises, consider dividing them in the fall after they have bloomed. To encourage strong blooming the following season you may also want to apply a fertilizer in the early fall months as the bulbs and tubers store nutrients that will be utilized the following year. Some summer blooming bulbs are not hardy to cold winter temperatures experienced in zones below 7 and should instead be lifted and stored for replanting. These include bulbs or tubers like dahlias, begonias, and cannas.
Lifting Bulbs and Tubers: Cut the stems a few inches above the ground and loosen the soil around the bulbs and tubers. Brush off any clinging soil and give them a quick rinse. Remove and discard any rotten portions to prevent further spread and maintain the health of your bulbs and tubers. Allow them to dry in an area with little light and good air circulation. This will help prevent mold growth while in storage. We recommend storing them in a cardboard box or paper bag in a dark, well-ventilated area where they won’t freeze. Check on them periodically for signs of rotting and remove them promptly to prevent any spreading.
Tubers
Tubers are thickened underground stems that store nutrients with no protective outer layer. They do not have a regular shape and often appear as very large roots. Multiple “eyes” will form around the tubers from which growth shoots will emerge. Typically, tubers only need to be covered with a few inches of soil, with any developing shoots facing upward near the surface. Potatoes are considered tubers that can be cut into multiple planting pieces with at least one eye on each.
Bare Roots and Crowns
Bare roots and crowns are dormant root networks that are ready to be transplanted. These typically include plants that will naturally spread over time, such as asparagus and strawberries. Bare roots are one of the most common plant forms you will see in local nurseries and greenhouses. In addition to flowers and edible perennials, dormant woody shrubs, trees, grapes, and berries will often be sold as bare-root plants during the early spring months. Crowns are where the sprouting point meets the root network. When planting bare roots, the crown should be positioned at the surface level with the roots covered.
Edible Roots and Bulbs
In addition to planting vegetable and herb seeds, plan to include roots and bulbs in your seasonal vegetable garden plans.
Garlic Bulbs - Garlic is a fall-planted bulb. Unlike flower bulbs, the garlic should be broken into individual cloves for planting. Larger cloves typically develop into larger bulbs. Harvest garlic bulbs in the summer around June-July. Hardneck garlic will develop a scape (flower stalk) during the spring. Remove these and use as you would green onions.
Strawberry Roots - While strawberries can be grown from seed, planting from bare roots (crowns) is more popular. Strawberries are planted in the spring once the soil is workable. For better establishment and larger crops in subsequent years, consider removing the flowers that form during the first year. Runners will develop to expand your strawberry patch and produce a strong harvest in the second and third years.
Asparagus Crowns - Asparagus is commonly referred to as a “ditch weed” as it is known to spread like crazy. Be sure to grow in a location where it has space to spread via the root system. Like strawberries, waiting to gather a full harvest until the second or third year is best. Asparagus should be planted in the spring once the soil is workable. You will want to dig a ditch for planting with room to fill in as the shoots grow.
Seed Potatoes - “Seed Potatoes” refers to potato tubers that are sold with the purpose of planting. They are not actual seeds. While potatoes can be planted from seed, they are overwhelmingly more popularly planted from tubers. When you plant a potato tuber, you are growing a natural genetic clone of the parent plant. Because potatoes develop off of the buried stem of the potato plant, you will want to plan on “hilling up” throughout the season. This practice keeps the tubers covered. If exposed to light, they will develop a green color, which can be toxic. Do not consume green potatoes.
Onion and Shallot Sets - Onion and shallot sets are bulbs that are ready for planting. These bulbs were grown from seed and harvested prematurely. When planted, they will grow into a full and mature onion. Onion and shallot sets are commonly grown to reduce the time to harvest from planting to a mere 60-80 days (100-120 for shallots) compared to 100-120 required when growing from seed (120-150 for shallots). This can be especially useful when growing in regions with short growing seasons.
Rhubarb Crowns - Rhubarb crowns are divisions from established plants. They usually have multiple buds along the crown, which should be planted at surface level. Unlike other bare root vegetables such as asparagus, rhubarb roots can be especially large or thick and vary considerably in size. Do not harvest or consume rhubarb leaves or roots as they contain oxalic acid and anthraquinone glycosides, which are harmful when ingested. Only the stalks are edible. The stalks are a red-pink color and are commonly used in jams, sauces, and pies.