Leo Berbee Bulb Company: News and Information


Spotlight: Precooled Bulbs

Why use precooled bulbs for cut flower farming?

Growers use precooled bulbs to gain significant control over bloom timing and to ensure the production of high-quality, long-stemmed flowers for market. Leo Berbee provides the necessary cold period, known as vernalization, that many spring-flowering bulbs like tulips, hyacinths, and crocuses need to develop roots and flower buds properly. This is especially crucial in warmer climates, where natural winter chilling is insufficient or when aiming for early forcing to meet specific market demands.

Precooled bulbs also allow farmers to extend their growing season and stagger harvests. By forcing early blooms for peak demand periods, they offer fresh flowers outside of their natural outdoor season and maintain a consistent supply of various bulb varieties.

Precooling also dramatically improves flower quality, resulting in the desirable long, strong stems that command better prices, more consistent and uniform blooms, and vibrant colors.

In essence, precooling empowers cut flower farmers to produce exactly what the market demands, when it demands it, leading to a more profitable and reliable business.


ABOUT LEO BERBEE'S PRECOOLED BULB PROGRAM

Leo Berbee’s Precooled Bulb Program runs from late fall through mid-to-late February, providing growers with premium bulbs ready for successful forcing.

We place our premium bulbs in cold storage at 41°F (5°C), starting in late September. This ensures they meet the specific cooling requirements essential for successful forcing. While different bulb varieties have unique chilling needs, we can handle a significant portion of the process through dry cooling at our facility. This means you'll receive your bulbs prepped and ready to finish their chilling period on your schedule, accommodating your specific forcing timeline.

Shipping typically begins in early November and continues through mid-to-late February, and you pick your desired ship week.

Tulip Precooled Bulbs: Growing Tips

Temperature control is essential when forcing precooled bulbs.

  • An average of 16 weeks of cooling is necessary to develop strong roots and ensure beautiful spring blooms.
  • We can dry cool your bulbs at 41°F (5°C) for up to 13 weeks (16 weeks total cooling minus the last 3 weeks), then ship them to you for the final three weeks of cooling
  • Precooled bulbs can root in hydro trays or black crates but must be stored at 41°F (or as low as 36-38°F) with very low light exposure.
  • After 3-4 weeks, you should see roots in hydro trays or emerging from the bottom of black crates.
  • At this point, they can be moved to a properly ventilated greenhouse at 65-68°F (18-20°C) with careful moisture control for 4 more weeks until they bloom.


Hydroponic Trays: Forcing Tulip Bulbs


Watch a video with Daniel from Petal Pickers on growing tulips hydroponically. CLICK HERE.


FORCING TULIPS HYDROPONICALLY

An extremely productive and less messy method of forcing bulbs is to use Hydroponic Trays. After giving the proper cooling (see above), put a Hydroponic Tray inside a bulb crate. Then place bulbs in the tray, up to 80 Tulip bulbs per tray, and add water. Place in a cooler to keep at 41°F (but as low as 36-38°F) for 3-4 weeks to root. Once roots are established, move tray to a properly ventilated greenhouse to grow at 65-68 degrees, with careful moisture control, for 4 more weeks to bloom.

While growing in the Hydroponic Trays, it’s important to keep water levels up and very fresh. You cannot overfill the trays as excess will drain out. Do not apply water onto the top of the bulbs, but add water around or between bulbs. Drain holes in the trays make it easy to flush out old water to replenish with fresh water.

FORCING TULIPS FOR VALENTINE’S DAY

Cool at 48°F by your preferred method. Bring into the greenhouse January 5.

FORCING TULIPS FOR EASTER

4 weeks at 58-68°F.                                                                                          

After planting, keep bulbs at 48°F until the roots grow out of the bottom of the container. When the roots show, drop the temperature to 41°F. Maintain this temperature until early January - depending on sprout development - the temperature needs to be lowered to 34°F and held until brought into the greenhouse. If a cooler facility is not available, the bulbs can be planted outside under a 6" layer of sand and straw (this method is only recommended in the Northern states where outside soil temperature makes it possible to do this).