How To Plant And Store Bulbs In Fall
1. Choosing The Right Bulbs For Boise’s Climate
The Treasure Valley is ideal for a wide variety of spring-blooming bulbs. Some of the best bulbs for our area include:
- Tulips: Classic and bright, tulips thrive in Boise’s well-drained soil.
- Daffodils: These hardy perennials are resistant to pests like deer and squirrels.
- Hyacinths: Known for their intense fragrance, hyacinths are another great choice.
- Crocus and Snowdrops: For the earliest splash of color, crocuses and snowdrops often bloom before winter has fully passed.
2. Timing: When To Plant Flower Bulbs
Fall is THE time to plant bulbs for spring blooms. You want to aim to have your bulbs are in the ground before the first hard frost but it ok if you plant a little later. In Boise, aim to plant your bulbs in late September to early November. The cooler temperatures allow the bulbs to establish roots before the ground freezes.
3. Planting Depth And Spacing
The general rule of thumb for planting bulbs is to plant them at a depth of about two to three times the height of the bulb. Here's a quick guide:
- Tulips and Daffodils: Plant 6 to 8 inches deep.
- Hyacinths: Plant 4 to 6 inches deep.
- Crocus and Snowdrops: Plant 3 to 4 inches deep.
Space bulbs about 4 to 6 inches apart for a dense, natural-looking display or you can spread things out a bit further for pops of color. Ensure that the pointed end of the bulb is facing up, as this is where the stem will emerge.
4. Soil Preparation
Bulbs need well-drained soil to avoid rotting. If your garden soil is heavy with clay, mix in a little potting soil to improve drainage. Before planting, you could also consider applying a bulb-specific fertilizer to give your bulbs an extra boost of nutrients.
5. Watering and Mulching
After planting, water your bulbs thoroughly. This helps settle the soil and encourages root growth. While fall rains usually provide enough moisture, ensure the bulbs aren’t sitting in overly wet soil. A 2- to 3-inch layer of mulch can also help retain moisture and protect the bulbs from temperature fluctuations.
6. After Planting: Winter Care
Once your bulbs are in the ground, they require little attention during the winter months. However, if you are worried about a particularly cold winter or a lack of snow cover, you may want to add an additional layer of mulch to insulate the bulbs from extreme cold.
Preparing Your Sensitive Bulbs For Winter
Now that your spring-blooming bulbs are in the ground and prepared for winter, it’s time to turn your attention to your tender or sensitive bulbs that won’t survive the cold.
In Boise, Idaho, some flower bulbs and tubers that typically need to be dug up before winter due to their sensitivity to cold include:
- Cannas
- Dahlias
- Gladiolus
- Tuberous Begonias
- Caladiums
1. Hard Freezes
If the weather in your area has led to a hard freeze (temperatures that are sufficiently cold, for a long enough period, to seriously damage or kill seasonal vegetation), it is time to dig up your sensitive bulbs. Certain plants that grow from bulbs do excellent in the Treasure Valley, but can’t survive our cold winters.
2. Cut Them Back
Cannas and Dahlias are two plants that fall into this category. With a little effort, you can enjoy your sensitive bulbed plants year after year. After a hard frost, cut the stalks down to 8-10 inches above the ground. This stem will give you a handle to work with when you loosen the bulbs from the soil.
3. Wait For Hardening
Wait 10 days before you dig, allowing the bulbs to harden off and the stem to dry out. After 10 days, use a pitchfork and loosen the soil on each side of the stem. Be sure to leave at least 1 foot of space on each side of the stem to ensure that you do not pierce the bulbs.
4. Clean
With the soil loosened, you can lift the stem and bulbs out. Wash all the dirt from the bulbs and set them out to dry. If the temperature drops below freezing at night, cover the bulbs with a blanket or sleeping bag. After 2-3 days, the bulbs should be dry enough for storage.
5. Storage
Pack the bulbs in vermiculite in a box. It is important that moisture does not build up in the box, but that the bulbs are also protected from drying out. Store the bulbs in a basement or a protected garage. The bulbs must be protected from freezing.
If you check the bulbs every few weeks during the winter, you will be able to make sure they are doing okay. If you see any mold, powdered sulfur can be dusted onto the bulbs to stop its progress. Temperatures should range from 35-45 degrees. In the spring, when you are ready to replant the bulbs, they can be separated if necessary.