How to Make Nectar for Bees: A Safe Sugar Syrup Recipe

A safe sugar syrup for bees is made from plain white granulated sugar dissolved in water, using either a 1:1 or 2:1 sugar-to-water ratio by weight depending on the season. No coloring, no flavoring, no boiling. The recipe itself is simple, but the details around it matter more than most beekeepers realize, because the wrong sugar, the wrong preparation method, or the wrong timing can sicken or kill a colony.

The Basic Recipe

There are two standard concentrations, and the season determines which one you use. In spring and early summer, when colonies are building up and need to simulate a nectar flow, mix one part white granulated sugar to one part water by weight. This thin syrup mimics the sugar concentration of natural flower nectar. In late summer and fall, when the goal is to help bees pack away winter stores, mix two parts sugar to one part water. The thicker syrup requires less effort for bees to evaporate down to a storable consistency, saving them energy heading into cold months.

To make either version, heat your water until it is warm but not boiling. Stir in the sugar until it dissolves completely. Let it cool to room temperature before offering it to the bees. That is the entire process. The emphasis on not boiling is not fussiness; it is chemistry, and the reasons are worth understanding.

Why White Granulated Sugar and Nothing Else

Natural nectar is built on three simple sugars: sucrose, glucose, and fructose. A plain white sugar syrup is essentially a sucrose solution, and honey bees have the enzymes to break sucrose into its component glucose and fructose efficiently. This makes white granulated sugar the closest practical match to what bees encounter in flowers.

The temptation to use “healthier” or “more natural” alternatives is strong, but nearly every substitute introduces problems. Brown sugar, raw sugar, turbinado sugar, and molasses all contain impurities and minerals that bees cannot digest well. These residues accumulate in the gut and can cause dysentery, especially during winter when bees are confined to the hive and cannot take cleansing flights. Powdered (confectioner’s) sugar often contains cornstarch as an anti-caking agent, which is similarly indigestible. Organic cane sugar is acceptable only if it is fully refined and white; if it has any brown tint, it carries the same risks as raw sugar.

Honey from unknown sources is also a poor substitute for syrup when feeding bees. It can harbor spores of bacterial diseases and viruses. Feeding honey from another colony or a store-bought jar risks introducing pathogens directly into the hive.

Sugars That Are Actively Toxic

Some sugars do not just cause digestive trouble; they poison bees outright. Mannose, a sugar found in some plant-derived syrups and occasionally in cheap sugar blends, is lethal to honey bees even in small amounts. Bees lack the enzyme needed to process mannose once it has been phosphorylated inside their cells. The result is that mannose-6-phosphate accumulates, blocks normal sugar metabolism, and kills the bee.

1PubMed. Enzymatic basis of mannose toxicity in honey bees

High-fructose corn syrup (HFCS) presents a different hazard. While some large-scale commercial beekeeping operations do use HFCS, it carries a well-documented risk: it contains and readily generates hydroxymethylfurfural (HMF), a compound that is toxic to bees. HMF forms when sugars are exposed to heat and acidic conditions, and HFCS is particularly prone to it. Even HFCS stored at warm temperatures for extended periods can develop dangerous HMF levels without any additional heating.

2PubMed. Formation of hydroxymethylfurfural in domestic high-fructose corn syrup and its toxicity to the honey bee (Apis mellifera)

The Danger of Overheating Your Syrup

HMF does not only come from corn syrup. It forms in any sugar solution that is heated too aggressively, including white sugar syrup. This is the real reason beekeepers are told not to boil their syrup. When you boil a sucrose solution, particularly for an extended time or at a rolling boil, HMF begins to form. The more acidic the solution and the longer it cooks, the more HMF accumulates.

The effects on bees are not immediate, which makes the danger easy to underestimate. Research on caged adult bees found that negative effects from HMF did not show up in the first two weeks of exposure. But between 15 and 30 days, bees fed HMF-contaminated syrup showed midgut cell death and increased worker mortality across treatment groups.

3Diversity. Hydroxymethylfurfural Affects Caged Honey Bees (Apis mellifera carnica)

For larvae, the toxicity picture is somewhat different. In lab studies, HMF concentrations ranging from 5 to 750 parts per million did not increase larval or pupal mortality compared to controls. But at 7,500 ppm and above, larval mortality hit 100 percent. The researchers calculated a lethal concentration for 50 percent of larvae at roughly 4,280 ppm after seven days and about 2,420 ppm by day 22, showing that toxicity compounds over time.

4PubMed. Effect of hydroxymethylfurfural (HMF) on mortality of artificially reared honey bee larvae (Apis mellifera carnica)

The practical takeaway: warm your water just enough to dissolve the sugar and stop. If you accidentally bring it to a boil, it is not the end of the world for a brief moment, but prolonged boiling or caramelization is a genuine risk. If the syrup takes on any amber or brown color from cooking, discard it and start over.

How Sugar Syrup Compares to Real Nectar

Sugar syrup is emergency food, not a perfect replica of what bees collect from flowers. Natural nectar contains all three major sugars (sucrose, glucose, and fructose) but also carries amino acids, lipids, vitamins, and secondary compounds like alkaloids and terpenes. All 20 of the standard amino acids found in proteins are present in nectar, though the total amino acid concentration is quite low compared to the sugar concentration.

5Philosophical Transactions of the Royal Society B: Biological Sciences. Sweet solutions: nectar chemistry and quality

Sugar syrup provides calories but essentially none of the micronutrients, amino acids, or phytochemicals that bees get from natural forage. This is why feeding should be thought of as supplementation during dearth periods or emergency rescue for starving colonies, not as a long-term replacement for real foraging. Bees that rely on syrup alone for extended periods are nutritionally compromised in ways that white sugar simply cannot address. Pollen and pollen substitutes are needed for protein; syrup covers only the carbohydrate side.

What Sucrose Does Inside the Hive

When bees consume sucrose syrup, they break it down with the enzyme invertase into glucose and fructose, then process it much like natural nectar. But the gut microbiome responds to sucrose in a specific way. Research on adult honey bees found that sucrose feeding fueled the growth of certain low-abundance bacteria that metabolize sugars into simpler compounds and then into acetate. Bacterial families including Rhizobiaceae and Acetobacteraceae increased two- to five-fold when bees were fed sucrose, compared to other carbohydrate sources.

6Europe PMC / Public Library of Science. The effect of carbohydrate sources: Sucrose, invert sugar and components of mānuka honey, on core bacteria in the digestive tract of adult honey bees (Apis mellifera)

Whether this shift is beneficial, neutral, or harmful over the long run is still an open question. The gut microbiome of honey bees is tightly linked to disease resistance and overall colony health, and long-term feeding with syrup rather than diverse nectar sources likely alters it in ways researchers are still mapping. This is one more reason to view sugar syrup as a temporary bridge, not a permanent diet.

Storing Syrup and Preventing Fermentation

Sugar syrup ferments. It is a warm, moist, sugar-rich solution with no preservatives, which makes it an ideal substrate for yeasts and other microorganisms. At room temperature, a batch of 1:1 syrup can start fermenting within a few days, especially in warm weather. Fermented syrup produces ethanol and off-odors, and feeding it to bees is a bad idea. Research has shown that honey bees consuming ethanol-containing sucrose solutions develop dose-dependent motor impairment, spending more time stopped or flipped upside down, with behavioral recovery taking anywhere from 12 to 48 hours depending on the dose.

7Europe PMC. Acute ethanol ingestion produces dose-dependent effects on motor behavior in the honey bee (Apis mellifera)

To avoid fermentation, make only as much syrup as your bees will consume within a few days when using 1:1 syrup. The thicker 2:1 syrup resists fermentation longer because its higher sugar concentration inhibits microbial growth, but even it will eventually spoil at room temperature. Refrigerating unused syrup extends its life to about two weeks. If you see bubbles forming on the surface, smell sourness, or notice a film developing, dump it and make a fresh batch. Moldy syrup should also be discarded without question.

Feeder hygiene matters as much as syrup freshness. Whatever type of feeder you use, rinse and clean it each time you refill. Residual syrup left in a feeder between fills grows bacteria and yeast, inoculating every fresh batch you pour in. A quick scrub with hot water and a small amount of white vinegar, thoroughly rinsed, is sufficient.

Additives People Put in Syrup (and Whether They Should)

Beekeepers frequently add essential oils, vitamins, protein supplements, or herbal extracts to sugar syrup. The evidence on most of these is mixed at best. A study testing several common natural products found that lemongrass oil and spearmint oil were generally safe for bee consumption and appeared to have some health-promoting effects. Brazilian propolis extract actually lengthened worker lifespan in the study. However, thyme oil, which is widely used as a hive treatment for Varroa mites, proved toxic at field-realistic dosages when consumed as a feed additive.

8PubMed Central. Effects of ingested essential oils and propolis extracts on honey bee (Hymenoptera: Apidae) health and gut microbiota

The distinction between applying thyme oil as a Varroa treatment (where bees encounter it mostly through vapor) and mixing it directly into feed (where bees ingest concentrated doses) is an important one. What is safe at one exposure route can be harmful at another. If you want to add essential oils to your syrup for their purported antimicrobial effects, lemongrass and spearmint appear to be safer bets than thyme, but even these should be used sparingly and at low concentrations.

Apple cider vinegar is another common additive, often added at a teaspoon per quart of syrup. The idea is that it slightly acidifies the syrup, discouraging mold and mimicking the pH of honey. There is some practical logic to this, and it has a long history in beekeeping tradition, but it has not been rigorously studied for efficacy or safety in controlled trials. A small amount is unlikely to cause harm, but it is not a substitute for good feeder hygiene and prompt syrup replacement.

When and Why to Feed

Feeding is not something you should do routinely as a matter of course. Bees do better on natural forage whenever it is available. The situations that call for syrup feeding are specific:

  • New colonies: A package of bees or a newly caught swarm installed on bare foundation has no stored food. Thin syrup (1:1) helps them draw comb and build up quickly.
  • Dearth periods: In midsummer, many regions have a gap between spring and fall blooms when little nectar is available. Light feeding can prevent starvation.
  • Fall stores: If a colony’s honey reserves are too low heading into winter, thick syrup (2:1) gives them a chance to pack away enough carbohydrate to survive.
  • Emergency rescue: A colony that is visibly starving, with bees lethargic and no capped honey visible, needs immediate feeding regardless of season.

Feeding during a nectar flow is wasteful and can cause problems. Bees will store syrup alongside honey, and if supers intended for harvest are on the hive, the resulting “honey” will be diluted with processed sugar syrup. Research has confirmed that when colonies are fed various sugar syrups at high volumes, the resulting honey shows detectable adulteration in its carbon isotope signature, and detection becomes easier the more syrup a colony receives.

9PubMed. Detection of adulterated honey produced by honeybee (Apis mellifera L.) colonies fed with different levels of commercial industrial sugar (C₃ and C₄ plants) syrups by the carbon isotope ratio analysis

For this reason, always remove honey supers before feeding syrup, and never harvest frames that were on the hive during a feeding period. The rule is straightforward: feeding boxes and harvesting boxes should never be on the hive at the same time.

Feeder Types and Placement

How you deliver the syrup affects how quickly bees take it, how much drowning occurs, and how much robbing from neighboring colonies you invite. The most common options each have trade-offs.

  • Hive-top feeders: A reservoir that sits directly on top of the brood box, covered by the outer cover. Bees access syrup through a screened channel. Holds a large volume and is protected from robbers. Downsides include drowning risk if the design is poor and difficulty checking levels without cracking open the hive.
  • Frame feeders: A plastic or wooden trough that hangs inside the hive in place of a frame. Bees access syrup from inside the hive, reducing robbing. Drowning is a significant problem without floats or textured interior surfaces for bees to grip.
  • Entrance feeders: A jar inverted over a feeding tray at the hive entrance. Easy to monitor and refill without opening the hive. The major drawback is that exposed syrup at the entrance advertises food to robber bees and wasps, and in a dearth period, this can trigger aggressive robbing behavior.
  • Baggie feeders: A zip-lock bag filled with syrup, laid flat on the top bars, with a few small slits cut in the upper surface. Cheap, no drowning risk, and minimal robbing since the syrup is inside the hive. Works well for short-term feeding but holds limited volume and needs to be replaced each time.

Regardless of feeder type, feed in the evening when possible. Delivering a large amount of syrup in the morning can trigger excited foraging behavior, and scout bees returning to announce a sugar source can attract robbers from other colonies, particularly during a dearth.

Disease Transmission Through Shared Feeding

Open feeding, where syrup is offered in a communal trough or pan away from hives, is sometimes recommended for its convenience but carries a serious risk. When bees from multiple colonies drink from the same source, they can transmit pathogens to one another. This is not a theoretical concern. Experimental work has demonstrated that infected honey bees readily transmit deformed wing virus (DWV-A) to bumblebees through direct contact, with 100 percent of recipient bumblebees becoming infected after just seven days of shared exposure in one study.

10PubMed Central. Experimental cross species transmission of a major viral pathogen in bees is predominantly from honeybees to bumblebees

Open feeding creates exactly the kind of close-contact mixing that facilitates this cross-colony and cross-species transmission. If you manage multiple hives, feed each colony individually using hive-specific feeders. If you are feeding bees you do not manage, say as a gardener or hobbyist wanting to support pollinators, sugar syrup in open dishes is not the right approach. Planting bee-friendly flowers is a far safer and more nutritious way to help.

Feeding Solitary and Native Bees

The entire recipe and discussion above applies specifically to managed honey bee colonies. Solitary bees, mason bees, bumblebees, and other native pollinators should generally not be fed sugar syrup. Their nutritional needs differ significantly from those of honey bees, and many of them do not even consume liquid nectar in the same way. Bumblebee colonies, for instance, operate on a much smaller scale and can be harmed by the microbial risks that accompany sugar water left out in the open.

If you want to support native pollinators, the evidence consistently points toward habitat improvement rather than supplemental feeding. Planting diverse, locally adapted flowering plants that bloom at different times through the season provides the full spectrum of nectar and pollen that these bees need. A dish of sugar water in your garden, while well-intentioned, is no substitute for a patch of wildflowers and carries real risks of spreading disease between visiting bees of different species.