By Austin Little
Screened bottom boards add airflow and make mite monitoring easy. Solid boards hold heat and keep drafts out. Which one is right depends on your weather, your pests, and how you use it.
AI disclosure. This page was drafted with AI assistance and edited for Apiary. We don't invent quotes, stats, people, or events. If something looks off, tell Austin — that's the point of a living hive.
Here's the short answer. In hot or humid climates, a screened bottom board is a common choice for airflow, usually left open most of the year. In cold-winter climates, many beekeepers still use screened boards but close them with the insert or tray in winter. Others prefer solid boards for the coldest months. In mild, damp, or windy places, a screened board with a removable insert lets you decide season by season. Either way, the most useful thing about a screened board is that it lets you slide in a sticky board for mite monitoring. Don't count on the screen itself to control mites. The evidence that screens alone meaningfully reduce Varroa is weak.
Both types work. Colonies survive on both.
What each bottom board actually is
A solid bottom board is a wooden (or sometimes plastic) floor under the hive, usually with a rim on three sides that creates the entrance at the front. It's the traditional Langstroth bottom. Many are reversible, with a deeper entrance on one side and a shallower one on the other.
A screened bottom board replaces most of that floor with a mesh screen. The bees walk on the screen. The mesh is sized so bees can't get through it but small debris and some mites fall through. Most screened boards have a slot underneath for a removable insert, tray, or sticky board. With the insert in, the board behaves more like a solid one.
Some beekeepers also use hybrid setups: a solid board with a screened section, a ventilated rim, or a screened board they keep closed most of the time.
Why people choose screened bottom boards
Easy mite monitoring
This is the best reason. Slide a sticky board (a white board coated with something sticky, or with a grid printed on it) under the screen for a set time. Mites that fall off bees land on it. Count them. That gives you a rough read on mite pressure over time.
It isn't the most precise monitoring method. Many guides prefer an alcohol wash or sugar roll for a decision-grade count.
The tray also catches other debris, which tells you things:
- Wax cappings in lines show where bees are uncapping honey, which roughly shows where the cluster is in winter.
- Chalkbrood mummies show a fungal brood problem.
- Wax moth droppings or larvae show a moth problem.
- Small hive beetle larvae may show up in beetle regions.
- Pollen pellets of different colors show what's blooming.
Ventilation
Bees manage temperature and humidity actively. They fan, cluster, and collect water. Extra airflow from the bottom can help in heat and humidity. In very hot weather, an open screen may make it easier for the colony to keep the brood nest from overheating. That's why screened boards are popular in hot regions.
Moisture management
In cool, damp weather, warm moist air from the cluster rises and condenses on cold surfaces, especially the lid. Cold water dripping on bees is bad. Some beekeepers find a screened board helps air move through the hive and carry moisture out, especially when paired with an upper vent. Others find a closed bottom and good upper ventilation work better. Moisture management is a whole-hive question, not just a bottom-board one.
Some debris falls out
Small debris and dead mites fall through the screen instead of collecting on the floor. Some beekeepers like having less litter for wax moths and beetles to use. Whether that matters much depends on your pests and colony strength.
Mites that fall don't climb back
Some mites fall off bees naturally or during grooming. On a solid floor, a few may climb back onto bees. On an open screen, they fall away. This is part of the original appeal of screened boards. But research and field experience suggest this effect alone doesn't control mites. You still have to monitor and treat based on counts.
Why people choose solid bottom boards
Warmth and fewer drafts
A solid bottom holds heat in and blocks wind from below. In cold climates, some beekeepers believe a solid bottom helps colonies conserve energy in winter and get brood rearing going sooner in early spring. Others think strong colonies do fine with an open screen.
Simplicity
A solid board has no insert to forget, no tray to clean, and no screen to clog with propolis. It's one piece.
Cost and durability
Solid boards are often cheaper and simpler to build. Screens can rust, sag, get damaged, or get propolized over time.
Some pest considerations
In some setups, a solid bottom gives ants and other crawling pests fewer gaps. On the other hand, debris on a solid floor can harbor wax moth larvae or beetles in weak colonies. Which is better depends on your pests.
Climate by climate
These are broad starting points. Your local club will know what works where you live, and that beats any national rule of thumb.
Hot and dry (desert, inland heat)
- Screened boards are common, often left open most of the year.
- Shade, a water source, and good upper ventilation matter at least as much.
- Watch for heat stress: heavy bearding (bees clustered outside the entrance), fanning, and wax softening.
- In colder desert winters, some beekeepers close the insert for the coldest months.
Hot and humid (southeastern US style)
- Screened boards are popular for airflow.
- Small hive beetles can be a major pest in many humid areas. Some beekeepers use oil trays under screened boards to trap beetles and larvae that fall through. Others find the screen gives beetles more hiding spots. Ask locally what works.
- Mold and moisture in the hive are bigger concerns.
Cold winters (northern US, Canada, high elevation)
- Many beekeepers use screened boards with the insert in for winter. Others use solid boards, or switch boards seasonally.
- Upper ventilation and moisture management are critical. A cold, dripping lid can do more harm than an open bottom.
- Wind exposure matters. A screened board in a sheltered spot behaves differently from one on a windy hilltop.
- Some cold-climate beekeepers leave screens open all winter with strong colonies and report good results. Others close them. There isn't one answer.
Mild and damp (Pacific Northwest, foggy coastal areas)
- A screened board with a removable insert gives flexibility.
- Damp, cool weather can mean persistent humidity. Watch for mold on outer frames and condensation on lids.
- Elevating hives off damp ground helps either way.
Mild Mediterranean (much of coastal California)
- Winters are mild and often wet. Summers can be dry and warm, with a long dearth.
- Many beekeepers in these climates use screened boards year-round, sometimes closing the insert during wet, windy spells.
Windy sites anywhere
- Wind through an open screen can chill the brood nest. A windbreak or closing the insert helps.
- Strap hives so they don't blow over. That's true for any board type.
Using a screened board well
If you have a screened board, these habits make it work better.
Know when the insert should be in or out
A simple seasonal approach many beekeepers start with:
- Hot season: insert out, for airflow.
- Cold or wet, windy season: insert in, or partly in, for fewer drafts.
- Monitoring: sticky board in for a set period, then out.
Adjust based on your local climate and what your colonies do.
Do sticky board counts consistently
- Leave the sticky board in for the same length of time each check. Many guides use a few days and divide by the number of days for a daily drop.
- Count mites carefully. A magnifier helps. Ant debris, pollen, and wax bits can look like mites to a tired eye.
- Look for trends over weeks.
Keep it clean
- Scrape debris off sticky boards and trays.
- Don't leave a tray full of wax and debris for weeks, since wax moths and beetles may use it.
- Check that the screen isn't clogged with propolis or wax.
Don't forget the insert
A common mistake: putting the insert in for monitoring and forgetting it for months, or pulling it out in cold weather and forgetting to put it back. Put reminders in your log.
Check fit
The insert should slide in easily but fit closely. If gaps are big, bees may build comb under the screen or wax moths may get in. Some boards have the insert slot at the back, others at the front.
Using a solid board well
If you use a solid board, these habits matter more.
Clean the floor
Debris accumulates on a solid floor, especially over winter. A strong colony will clean it. A weak one may not. In spring, many beekeepers swap the bottom board for a clean one or scrape it out.
Plan another way to monitor mites
Without a screen, you can't use a sticky board the same way. (Some beekeepers slide a sticky sheet onto a solid floor, but bees walk on it and the sheet gets covered.) Use an alcohol wash or sugar roll on a schedule.
Pay attention to moisture
A solid floor doesn't let moisture out from below. Upper ventilation, such as an inner cover notch or a small upper entrance, becomes more important in cold, damp weather.
Tilt for drainage
A slight forward tilt helps rain run out the entrance instead of pooling on the floor. Keep it level side to side for straight comb.
Reading the tray: a closer look
If you use a screened board, the tray under it is a free daily report on the colony. Here's how to get more out of it.
Mites. Varroa are small, reddish-brown, oval, and wider than they are long. They look a bit like a tiny shield or a sesame seed turned sideways. Pollen grains, bits of wax, and dark debris can fool you. A cheap magnifier and good light help. Counting on a grid makes it easier to avoid counting the same area twice.
Cappings lines. In cool weather, the colony eats stored honey and drops the wax cappings below where it's working. Lines of wax debris under certain frames show you roughly where the cluster is and which way it's moving. If the debris lines are moving toward an outer wall and the outer frames are empty, the colony may be running out of reachable food. That's a cue to heft the hive or check stores.
Pollen. Colored pellets on the tray tell you the bees are bringing pollen in, which usually means brood rearing. A sudden absence of pollen in the active season can mean a dearth or a colony problem.
Chalkbrood mummies. Hard, white or gray-black lumps. A few are common in damp spells. Lots of them point to a stressed colony or a genetic tendency. Talk to your mentor.
Wax moth frass and larvae. Small dark pellets and webbing suggest wax moths. Strong colonies usually keep moths in check. A tray full of moth signs often points to a weak colony.
Small hive beetle larvae. In beetle areas, you may see small, creamy larvae with rows of spines on their backs. Beetle larvae on the tray mean beetles are breeding in the hive. That needs attention.
Dead bees. A few dead bees are normal. A sudden pile can mean poisoning, starvation, disease, or a robbing fight.
Buying or building a screened board: what to check
Not all screened boards are the same. Before you buy or build one, check:
- Mesh size and material. It should be fine enough that bees can't pass through, and sturdy enough not to sag. Galvanized or stainless mesh resists rust better.
- Screen attachment. Staples or a frame that holds the mesh tight. A loose screen sags, and bees can get under it.
- Insert slot. Does it slide in from the back or the front? Is the fit snug? Some slots leave gaps that bees or moths can use.
- Insert material. Corrugated plastic inserts are light and easy to clean. Some come with a printed grid for counting.
- Entrance options. Does it have a reversible entrance or a separate reducer? Does it work with your entrance reducer and mouse guard?
- Box size. Eight-frame and ten-frame boards aren't interchangeable.
- Match with your stand. Some stands sit right under the bottom board and block the insert slot. Make sure you can reach the tray.
If you're building, start with plans from a reputable supplier or extension service, and check them against the boxes you already own.
One year with a screened board: an example
Here's what one season might look like for a screened-board beekeeper in a temperate climate with cold winters. Adjust to your area.
- Early spring: Insert in on cold nights. Check the tray for cappings lines to see where the cluster is and whether stores are holding. Do a mite count as brood rearing ramps up.
- Late spring: Insert out once the weather settles, for airflow. Pull a sticky board count now and then to watch the trend.
- Summer: Insert out. Watch for heat stress. Monitor mites more often, since counts often climb. Confirm with a wash before treatment decisions.
- Fall: Do a careful mite count before winter preparations. Put the insert back in when the weather turns cold and windy, or follow your club's practice.
- Winter: Insert in or out per local practice. Check the tray now and then for cappings lines and dead bees.
Can you switch?
Yes. Bottom boards are one of the easiest parts of a hive to change. Many beekeepers:
- Keep a few of each type and swap seasonally.
- Start with screened boards and close them in winter.
- Use solid boards on overwintered colonies and screened ones on summer colonies.
To switch, pick a calm, warm day. Lift the whole hive body off (that's heavy, so get help, or use a hive lifting setup), set it on a temporary stand or an upturned lid, swap the bottom board, and put everything back.
What a bottom board won't fix
Mites. Neither type controls Varroa on its own. Monitor and treat based on counts.
A weak colony. A weak colony struggles with temperature, pests, and robbing whatever floor it sits on.
Bad ventilation elsewhere. Lid condensation, a blocked upper entrance, or a wet hive site matter more than the bottom board.
Bad placement. Shade, wind, damp ground, and flooding risk all matter. A hive stand that lifts the hive off the ground helps either way.
Common beginner questions
Do bees fall through a screened bottom board? No, if the screen is the right mesh size. Bees can't get through it.
Do I need to close my screened board in winter? Depends on your climate. In cold, windy areas, many beekeepers close it. In mild climates, many leave it open. Ask your local club.
Will an open screen let robbers in? Not if it's intact and the insert slot is closed off appropriately. Robbers come through entrances and gaps.
Can I use a sticky board on a solid bottom? Not very effectively. Bees walk on it. Use alcohol washes or sugar rolls instead.
Is a screened board worth it for a beginner? For many beginners, yes, mainly for the easy mite trend checks and the flexibility of the insert. It's not essential.
Will a screened board help with small hive beetles? It can be part of a beetle strategy, especially with oil trays, in some areas. Ask locally. Beetle pressure varies a lot by region.
A quick decision guide
- Hot climate, airflow matters most: screened, open most of the year.
- Cold windy winters: screened with insert in for winter, or solid. Strong upper ventilation either way.
- Mild damp climate: screened with removable insert, adjust by season.
- Want easy mite trend checks: screened.
- Want the simplest possible setup: solid, plus regular alcohol washes or sugar rolls.
- Not sure: screened with an insert, because it can behave like either.
How AI fits
An AI assistant can help you build a seasonal checklist for your insert, log sticky board counts, or chart trends. It can't tell you whether your colony is cold or your hive is wet. You find that out by looking at the bees, the lid, and the frames.
The bottom line
Screened bottom boards give airflow, flexibility, and an easy way to watch mite drop with a sticky board. Solid boards are simpler, hold heat better, and keep drafts out. Neither one controls mites. Neither one saves a weak colony or fixes bad ventilation elsewhere.
Match the board to your climate. Open screens are common in heat. Closed screens or solid floors are common in cold, windy winters. A screen with a removable insert lets you switch season by season. Whatever you choose, monitor mites with a method that gives you a real count, manage moisture through the whole hive, and check your local club's practice.
We are bees. We save bees. Sometimes that starts with what they stand on.