Most beekeepers feed plain white sugar syrup, not Karo corn syrup. Karo is a household corn syrup made for baking, and it is not the best choice for bees. Sugar syrup made from granulated cane or beet sugar and water is the standard emergency and seasonal feed. If you are thinking about corn syrup, here is what to know first.
Karo Syrup vs. Sugar Syrup
- Sugar syrup (sucrose): Plain white granulated sugar dissolved in water. Bees break sucrose down easily, and it is what most extension programs recommend.
- Karo (corn syrup): Consumer corn syrup is made mostly of glucose. It contains other sugars and compounds that bees may not digest as well, and flavorings such as vanilla in some versions are not meant for bee feed.
- High-fructose corn syrup (HFCS): Commercial beekeepers sometimes buy food-grade HFCS made for bees. It must be kept cool and fresh because heat can create hydroxymethylfurfural (HMF), a compound that is harmful to bees. This is different from the Karo bottle in your pantry.
Because bees do not have a proven benefit from Karo and there is a risk of problems, most beekeepers stick with plain sugar syrup.
How to Make Sugar Syrup
- Spring (1:1): Mix equal parts white sugar and warm water by weight or volume. This thinner syrup mimics nectar and encourages the colony to grow.
- Fall (2:1): Mix two parts sugar to one part water. This thicker syrup is easier for bees to store for winter.
- Stir until the sugar is fully dissolved. Warm water helps, but never boil the syrup, since overheating can create HMF.
- Let it cool before filling a feeder.
Do not use brown sugar, raw sugar or molasses. They contain solids that bees cannot digest and can make bees sick. Never feed honey from unknown sources, because it can carry disease spores.
When to Feed Bees
- New colonies and packages: To help them draw comb.
- Spring: When stores are low and flowers are not yet blooming.
- Late summer and fall: To build winter stores, if the colony is light.
- Dearth: When there is little nectar available.
Do not feed syrup while honey supers are on the hive if you plan to harvest honey, since the sugar can end up in your honey.
Feeder Types
- Entrance feeders: Simple, but they can encourage robbing by other bees.
- Frame feeders: Sit inside the hive and are less likely to cause robbing.
- Top feeders: Hold a large amount of syrup. Use floats or screens so bees do not drown.
- Jar or pail feeders: Inverted containers with small holes that sit over the inner cover.
Feed in the evening, keep spills cleaned up and reduce hive entrances if robbing starts.
Frequently Asked Questions
Can I use Karo syrup in an emergency?
If you have nothing else, a bit is unlikely to cause immediate harm, but sugar syrup is much safer and cheap. Mix a batch instead.
How long does sugar syrup last?
Refrigerated, it keeps for a week or two. Discard syrup that smells fermented or looks moldy.
How do I know if my bees need feeding?
Check the hive for stores. If you are unsure, ask a local beekeeping association, since needs vary by region.
Bottom Line
For bees, stick with plain white sugar syrup mixed 1:1 in spring and 2:1 in fall, never boil it, and skip household corn syrup. If you are new to beekeeping, ask a local beekeeping club about feeding schedules for your climate.
