Growing Bulbs in Colorado: How and When to Plant Spring-Blooming Bulbs
Remember how happy you feel when you see crocus, daffodils, and tulips popping up through the barely thawed ground after a long winter? Well now is the time to plant these spring-blooming bulbs in your flower gardens and landscapes! Planting bulbs is one of the easiest gardening tasks there is and come springtime, you will be thrilled you took the time to dig a few holes and drop in a few bulbs. With the many varieties and an endless array of colors, there is no limit to the fun combinations you can come up with to decorate your outdoor areas before any other plants begin to come back to life.
About Bulbs | When to Plant Bulbs | Where to Plant Bulbs | Bulb Sun Requirements | Bulb Watering Requirements | Bulb Soil Requirements | How to Plant Bulbs | How Deep to Plant Your Bulbs | Fertilizing Your Bulbs | Mulching Your Bulbs | Design/Planting Tips | Where to Buy Bulbs in Fort Collins, CO | Tutorial Video
Spring-blooming bulbs, also often referred to as fall bulbs or spring-flowering bulbs, include things such as tulips, daffodils, crocus, dahlias, gladiolus, lilies, and more! These bulbs are called fall bulbs and/or spring-blooming bulbs literally because they need to be planted in the fall but bloom in the spring. They need to be planted near the end of the growing season because bulbs like these require a chilling period in order to bloom. Planting in the fall allows them time to root during the winter so that they are ready to burst forth with color early in the spring as soon as the last of the snow melts away. For the longest lasting bulbs, we recommend choosing bulbs that are labeled as "naturalizing." Bulbs labeled as such will come up consistently year after year and will even multiply and spread throughout your garden in subsequent years, bringing you beautiful flowers indefinitely!
Planting and Growing Spring-Blooming Bulbs
Fall/spring-blooming bulbs are perhaps some of the easiest flowers to grow. And while it may take a few months before you get to experience the fruits of your labor, it is quite worth the wait! To help you be as successful as possible with planting and growing spring-blooming bulbs, here is a guide with all of our tips and recommendations.
When to Plant Spring-Blooming Bulbs
As we briefly mentioned above, bulbs need a chilling period if they are to bloom in the spring as expected. This is why they are often referred to as fall bulbs, because they need to be planted in the fall in order to bloom in the spring. Ideally, your bulbs should be planted six weeks before the ground freezes or when the average nighttime temperatures drop to 40-50 degrees. With Colorado's weather being so unpredictable, this can vary. However, it is usually safe to plant your bulbs sometime near the beginning/middle of October. This will more often than not give your bulbs enough time to root before the ground freezes for the winter season.
Where to Plant Spring-Blooming Bulbs
As with any other plants, where you plant your bulbs is the primary factor that will affect the size, beauty, and health of your bulbs. The right combination of soil, water, and light all play into the right location for planting. Here is what we recommend:
Sun Requirements for Bulbs
Most bulbs require full sun exposure for at least six hours per day. Many bulbs can tolerate partly shady areas, though they will thrive in direct sun. Since bulbs are one of the first plants to emerge in the spring, there are many places where they can be successfully grown. For example, since most deciduous trees will not yet have leaves by the time your bulbs begin to grow, you can even plant your bulbs at the base of trees or in other areas that might be completely shaded once your trees leaf out.
Water Requirements for Bulbs
Despite their lush and colorful appearance, most bulbs actually come from dry climates and do not require a lot of water. They are more likely to rot if they get too much water or are planted in soil that does not drain well. Because of this, we recommend watering your bulbs immediately after planting to help settle the soil, get rid of any air pockets, and encourage the roots to start growing. After this initial watering, you can (for the most part) let nature do the rest of the work. The only time you should really have to water your bulbs is if there are any prolonged dry spells. You can give them a quick spritz during their growing season, but really your bulbs should not need much extra water unless you are in a severe drought or have not gotten any sort of precipitation in a significant amount of time.
Soil Requirements for Bulbs
Planting your bulbs in soil that is well-draining is very important if you want to grow bulbs successfully. Since bulbs have a tendency to rot in conditions that are too moist, having soil that does not hold onto moisture will be key. Much of the soil here in Colorado is clay-heavy, dense, and holds onto a lot of moisture. We recommend replacing this soil entirely or heavily amending it with sand, peat moss, compost, or other soil amendments that will improve drainage in the soil. Also planting in an area with a gentle slope can help ensure good drainage. Definitely avoid planting your bulbs in areas where water naturally collects. Fort Collins soil can be improved with a wide variety of soil amendments from our Garden Center, so stop by to check out some products or get some advice from our plant pros!
How to Plant Spring-Blooming Bulbs
When you actually get to planting your bulbs, you will be surprised at just how easy it is! Planting spring-flowering bulbs is as easy as digging a hole, placing your bulbs in the hole, and covering it back up with soil. However, just to ensure your success in planting your bulbs, here are some additional details.
Planting Depth for Spring-Flowering Bulbs
A general rule of thumb for how deep to plant your bulbs is to plant them approximately two to three times deeper than their width/height. So, if a bulb is approximately 2 inches in diameter, it will need to be planted 4-6 inches deep. When you purchase your bulbs, there will also be information on the package specific to the variety you purchased, and we always recommend that you follow these instructions first and foremost! And if you are worried about not planting your bulbs deep enough or planting them too deep, just do your best. Bulbs that are planted at less than ideal depths have an interesting way of self-adjusting over the course of a year or two, digging themselves deeper into the ground until they have found their ideal depth.
Plant Your Bulbs Right Side Up
When placing your bulbs in the holes you have dug for them, try to plant them facing upwards. It is usually pretty easy to tell which side is the top and which is the bottom, as the top of most bulbs usually have a tip where the foliage emerges from in the spring. If your bulbs do not have this sort of shape, the bottom will likely be flat (or more flat than the rest of the bulb) and have a ring around the bottom where the roots will grow from. Some bulbs may even have some dried out, stringy, or hairy-looking roots already coming out the bottom. If you still cannot tell the top from the bottom, just plant your bulb on its side and it will likely still grow just fine, it may just take a day or two longer to fully emerge.
Add Fertilizer When Planting
If you plant your bulbs in soil that is less than ideal, it wouldn't hurt to add some fertilizer to each hole you dig to plant your bulbs in. A little extra phosphorus can also go a long way in helping your bulbs produce vibrant, colorful flowers. We recommend using a bulb-specific fertilizer or a bone meal fertilizer like the ones pictured below. When you plant your bulbs this season, they already have the embryo for next spring's flowers formed inside the bulb, so fertilizing now will not have a huge effect on the upcoming season's flowers. However, adding some fertilizer initially when planting and even lightly fertilizing your bulbs as the foliage begins to grow in the spring will help promote strong growth and will also give your bulbs some extra energy and nutrients as they begin to form embryos for the following season's flowers.
Add A Layer of Mulch
After you plant your bulbs, it is recommended to add a layer of mulch to cover the surface of the soil. Not only does this look nicer than just a bare layer of dirt, but also helps maintain a consistent soil temperature throughout the summer and the winter seasons, protecting your bulbs from any extreme temperatures. This layer of mulch also helps to preserve soil moisture throughout the summer and winter. We recommend covering your bulbs with 3-4 inches of mulch after planting. In the spring once all the snow has melted, you can remove some of the mulch or spread it around the rest of your garden beds so that there is only around a 1-2 inch layer of mulch covering your bulbs. This will make it easier for the foliage to push through the mulch layer when your bulbs begin to emerge in the spring.
When planting your bulbs, there are a few things you should consider in terms of how you arrange your bulbs, what colors you choose, or how many you choose to plant in a certain area. While your bulbs will look beautiful in the spring no matter what, there are a few planting strategies you can employ to maximize the visual effect of your bulbs and create a display of flowers that will make anyone stop and stare. For the best visual display, coordinate bloom times, bloom sizes, and bloom heights to ensure an interesting and colorful spring garden!
Plant Your Bulbs in Clusters
We recommend planting clusters of at least 15 large bulbs or 35-50 small bulbs for the best impact. If your tulips, crocus, or daffodils are too spread out, they will still look pretty, though they may not make quite as bold of a statement. Planting your bulbs within 2-4 inches of each other depending on the size of the bulb is generally what is recommended to avoid overcrowding while also maintaining a full and lush display.