The UK Bee Forage Bloom Calendar: Nectar Flow Through the Seasons

What a nectar flow actually is

A 'flow' is not simply a season when flowers are present; it is a period when the rate of nectar secretion across a landscape exceeds what the local bee population - honey bees, bumblebees and solitary bees combined - can immediately consume, so that surplus accumulates in the hive as honey. This distinction matters because a landscape can look floriferous to a human eye while offering almost no usable flow, if the flowers present are poor nectar producers, if competition from other pollinators is high, or if weather conditions are preventing nectar secretion or bee flight.

Nectar secretion itself is driven less by air temperature alone than by a combination of soil moisture, recent rainfall, humidity and daytime temperature acting on the specific physiology of each plant species. A prolonged dry spell can shut down secretion in many umbellifers and clovers even while the plants continue flowering visibly, which is why the same hedgerow can produce a strong flow one year and almost nothing the next.

A month-by-month sketch of the UK season

The beekeeping year typically opens in February and March with snowdrop, crocus, willow catkin and early flowering currant providing the first pollen after winter, crucial for restarting brood rearing rather than for honey surplus. April and May bring the first major flow window: blackthorn, fruit blossom, dandelion, sycamore and oilseed rape where grown locally can produce a strong, fast honey crop, though oilseed rape honey granulates quickly and needs prompt extraction.

Late May into June often brings the so-called 'June gap' - spring blossom has finished, hawthorn is over, and the main summer flow from bramble, lime and white clover has not yet started, leaving colonies that have built up strongly during the spring flush suddenly short of incoming forage. July typically brings the strongest flow of the year where lime, bramble and clover are locally abundant, tapering through August as most herbaceous forage finishes. September and October rely heavily on ivy for both nectar and pollen, often the last substantial forage event before colonies cluster for winter.

Building a calendar for your own apiary

A generic national calendar is a useful starting template, but actual flow timing shifts by two to four weeks between a sheltered southern garden and an exposed northern or upland site, and varies further with local land use - an apiary surrounded by arable farmland, permanent pasture or mixed woodland edge will each have a distinctly different calendar. The most reliable way to build a site-specific calendar is direct observation over several seasons: noting when pollen colours change on returning foragers, when hive weight on a scale begins climbing steadily rather than plateauing, and when specific plants nearby come into flower.

Recording this over three or four years, even informally, reveals the pattern far more reliably than any published calendar, because it captures your specific microclimate, soil type and the forage plants actually available within typical foraging range of the hive, rather than a generalised regional average.

Monitoring the flow rather than guessing

Hive scales are the single most informative tool for tracking a flow in real time: a sustained daily weight gain signals an active flow, while a flat or declining scale despite fine weather signals a dearth, prompting a decision about feeding or moving colonies. In the absence of a scale, watching forager traffic at the entrance, the fullness of returning bees' abdomens, and the rate at which new comb is drawn on a flow all give a rough but useful proxy.

Weather forecasting adds a predictive layer: a settled warm spell with light rain forecast a few days prior often precedes a strong flow, as moisture recharges nectar secretion just before conditions turn favourable for both plant flowering and bee flight. Beekeepers who correlate their own records against the Met Office's regional data over several seasons develop a genuinely useful local forecasting sense.

Using the calendar to plan siting and feeding

Once a reasonably reliable calendar exists for a site, it becomes a planning tool rather than just a record. Apiaries can be sited to access the earliest possible spring pollen (willow, hazel) to support buildup, while supplemental feeding can be targeted precisely at known gap periods - typically late May to mid-June in much of lowland England - rather than applied reactively once a colony is already showing signs of stress. It also informs swarm control timing, since colonies that build up fast on a strong spring flow are the ones most likely to reach swarming congestion just as the June gap approaches, a combination that catches out many second-year beekeepers.