Bulb flowers–especially common ones such as iris, tulips, daffodils, and crocus–are a great way to add color and beauty to your garden. They can be planted in the Fall or early Spring because of their cool weather preference. However, those in warmer climates (or those who forgot to plant them on time) may wonder if a quick trip to the freezer will help them maintain their cold period.
You can refrigerate bulbs before planting to encourage flowering shoots before they’re in the ground, but it’s not necessary. Just be sure to keep away from produce. However, if you’re planting your flowers during the right season, the ground will act as a refrigerator, cooling the bulbs.
Though this question may have many sources–those in warmer climates, those who forgot to plant their tulips in time, or those looking for a shortcut–the answer remains the same. Below, I’ll discuss why bulbs require chilling and why some gardeners swear by putting their bulbs in a fridge. Then, I’ll go over some other basics for bulb planting.
Bulbs Become Dormant in Cool Weather
Bulbs do best in cold weather, but how you negotiate is up to you. This is because the bulbs “hibernate” in the Winter, becoming dormant, and then re-bloom in the Spring when the weather heats them back up. They can photosynthesize underground as they die back, which is why they need to return to dormancy.
This is why some gardeners might think a period in the fridge is necessary for their bulb plants. Some common bulbs plants that grow in the Winter are:
- Hyacinths and daffodils
- Glads (gladiolus)
If you’re going to plant any of these flowers, you’ll need to start them 1 to 8 weeks before the date of the last expected frost, depending on the bulb. They need some time underground (or in the cold) to grow. Depending on your location, you could plant these at the end of Fall so they can settle before Winter.
However, this isn’t because they “need” cold necessarily. Again, it’s not necessary! It can work as a good quick fix if you’re planting too late in the season or as an easy way to ensure your bulbs are sprouting in the spring.
Some Gardeners Put Their Bulbs in the Fridge Before Planting
As mentioned above, some gardeners put their bulbs in the fridge before planting to watch them sprout before putting them underground. It’s not necessary, as we’ve already established, but whether or not you enact this tactic is your choice. The pros are that you can watch the bulb sprout or plant it underground post-refrigeration in mid-Spring if you forgot to plant them in the Fall or before the last frost.
However, I avoid this practice because it’s a slippery slope to disaster.
The refrigerator is great for many things, but it isn’t always the best place to store your flower bulbs. In fact, storing bulbs in the fridge before planting can ruin your chances of having a successful garden if you don’t do it right. You should store your bulbs in a brown paper bag or something protective and keep them away from fruits (which produce a gas that can harm your seeds). Make sure there is no moisture, or your bulb will be susceptible to rot.
Your fridge is also less predictable weather-wise than you might think, especially if you don’t have a newer model. Some refrigerators are too cold for most bulbs, and some refrigerators are also too warm for many bulbs. Bulbs need soil temperatures between 50°F and 60°F (10°C and 16°C) to sprout properly. Anything outside of those parameters can cause them to rot before they ever get a chance to flower!
Additionally, it’s difficult to decide the perfect time to pull your plants out of the fridge. If the roots have spent time in the fridge without nutrients from the soil, they may grow weaker than their underground counterparts.
Of course, a trip to the fridge is only one of the many things that can impact bulb growth. For example, unless you’re careful, your tulips may end up coming up stubby. To learn more about why this may be the case, you can refer to my other article: Why Are Your Tulips So Stubby? 4 Common Causes
Most Bulb Plants Are Cold Weather Plants
The winter months are a time of rest and regeneration for most bulb plants. The bulbs must be kept dormant so they don’t sprout prematurely in warmer temperatures. If you plant your bulbs too early, you risk having them rot or mildew before they have time to fully develop roots (which can cause them to die).
If your climate has warm winters and cool summers—such as the southern United States or California—you can plant your bulbs in Fall (October–December) after any danger of frost has passed. This is also true if you live in an area where winters aren’t cold enough for long periods of dormancy but still experience freezing temperatures every year. In these areas, it’s best to plant your bulbs in the Autumn so they’re ready for Spring when it comes around again.
If you live in a warmer climate and want to dig up your bulbs and store them in the fridge, you could attempt this and see if they’ll replant in the Spring. However, they may rot, and not everyone has room in their fridge for bulbs! Underground is truly the safest place for those bulbs to be in dormancy.
The Verdict: Try To Follow the Guidelines and Refrigerate as a Worst Case
Cold weather serves an important purpose for your bulb plants, but it mostly acts as a protective factor. The cool helps plant bulbs underground become dormant for the Winter when they won’t be synthesizing any longer. Putting your bulbs in the fridge before planting is unnecessary, especially if you’re planning ahead and planting your bulbs in the right season.
However, if you are a little late to the bulb planting party and want to cool your plants before putting them underground, that’s your choice!
Other Factors To Consider With Bulb Flowers
A plant’s hardiness zone determines how much cold it can handle, based on the average annual minimum temperature in your area. It’s important to know this because if you live in an area with extreme temperatures, you may need to choose more tolerant colder weather bulbs.
The bulb type also plays a role: some plants will perform better with certain types of soil (some prefer sandy soil, while others prefer clay). Planting also depends on the type of flower you’d like—some bulbs produce flowers with stalks or leaves until they bloom, while others just bloom once and then die off after their season is complete.
The Right Spot in the Garden for Common Bulb Plants
Bulbs are best planted at the correct depth, which is to say, they should be planted so that their base is just above the soil surface. Some gardeners suggest putting them deeper if you’re doing an early planting, such as in the Fall. In this case, you’ll want to plant it at a depth three times the height of your plant.
Watering Common Bulb Plants
Watering common bulb plants is an important part of caring for them. The watering frequency depends on several factors, such as the bulb type and the soil in which it is planted. It’s also important to consider how much rain you’ve had recently because if you water too much, your bulbs could rot.
Bulbs generally need less water than other plants because they’re dormant during Winter. As spring approaches and temperatures rise above freezing overnight, they start to grow again. This process continues until summer arrives, and the air stays warm all night, with temperatures around 55°F, or 12.78°C. At this point, it’s okay to stop watering your bulbs once every two weeks – however, don’t let them dry out completely!
If you’re unsure whether your plant needs more water yet, feel its soil with your fingers. If there are still wet spots under its leaves, give each one about half a cup of water at least once per week until the weather reaches full summer heat.
You don’t need to refrigerate your bulbs before planting–it may do more harm than good. However, if you do want to see the bulbs sprout and are going to be very attentive to them in your fridge, go for it. Just watch out for root rot and keep them away from any produce.