Your September Tropical Homestead Checklist

Mould is a fungus, a cousin of mushrooms, and it grows wherever things stay damp. It loves walls, shoes, books and the back of cupboards.

The US Environmental Protection Agency has advised keeping indoor humidity, the amount of water in the air, ideally between 30 and 50%. In the humid tropics that's hard, so aim at least for under 60%.

A cheap humidity meter, called a hygrometer, tells you where you stand, like a thermometer for dampness. Open the house whenever the rain stops, and let a fan push damp air out.

The CDC, the US health agency, says wet things should be cleaned and dried or thrown out within 24 to 48 hours to stop mould from growing.

Wet mattresses, carpets and cardboard boxes are the worst. If they can't dry in time, they're usually better gone.

Mould spores are tiny bits that float in the air and can irritate your lungs. So clean it up the safe way.

Wear an N95 mask, gloves and goggles. Scrub hard surfaces with water and detergent, then dry them fast. Never mix bleach with ammonia or other cleaners. If mould covers more than about 1 square metre, or someone at home has asthma or a weak immune system, get professional help.

Sometimes mould comes from inside the walls. In hot, humid places, a wall built the wrong way can trap water instead of drying out. Our guide to insulation explains how moisture moves through walls.

After weeks of rain, rivers can rise fast, even when it isn't raining where you are. Know the flood warnings for your area and where you'd go if the water came up.

The US National Weather Service says 15 cm of fast-moving water can knock an adult off their feet. Just 30 cm can carry off a small car, and 45 to 60 cm can carry away trucks and big SUVs.

Its rule is four words long: turn around, don't drown.

After every flood, August's well rule still holds: test the water for bacteria, even if it looks clear, and drink stored or bottled water until the well has been disinfected and a test comes back clean. Our guide to off-grid wells explains how to keep well water safe.

Floodwater carries mud, sewage and chemicals. Make sure tank lids, hatches and underground cisterns are sealed, so floodwater can't get into your drinking water.

So what should you plant in September in the tropics? Most planting guides are written for places with a spring and an autumn, but tropical gardens run on the rain calendar instead. Every place keeps its own, and the farmers around you know yours best.

One good guide comes from the University of Guam, on an island in the western Pacific north of the equator. On its table of common garden crops, this month opens a new window: yardlong beans, sweet corn and cucumbers can all be planted from September to April.

The year-round plants on that table continue too, including leafy greens, green onions, long eggplant, hot peppers, okra, bitter melon, sweet potatoes and taro. Cherry tomatoes and Chinese cabbage wait until October.

In Central America, this is when farmers sow the postrera, their second bean crop of the year, and harvest it by January, says the GEOGLAM Crop Monitor.

Climbing beans grow like crazy in the rains. Yardlong beans, the long thin beans of Asian kitchens, are ready to pick 55 to 60 days after planting on Guam, and then keep giving for about four weeks. Singapore's National Parks Board says the vines grow 2 to 4 metres long. That's about as high as a basketball hoop.

Beans and corn are big seeds, so they can go straight into the soil. But beans and cucumbers need support, says the Guam guide: a trellis, a frame of sticks and string they can climb. Push the stakes deep so a storm can't knock them over.

Plants up off the ground get more air, so their leaves dry faster after rain. Singapore's parks experts say yardlong beans grow best in full sun and cope well with humid air, but not with waterlogged soil. A layer of mulch, like straw or dry leaves, stops rain from splashing dirt up onto the leaves, the Guam guide adds.

Choose varieties made for the heat. On Guam, peas and brussels sprouts don't produce a crop, while lettuce, broccoli and kale grow quite well from the right seeds. Our off-grid garden guide covers watering, soil and space, and July's list explains which plants grow year round.

The World Health Organization says moulds grow on food in warm, damp and humid conditions, and some make poisons. Keep grain, beans and flour in sealed containers off the floor, and check them often. As in March, anything mouldy, discoloured or shrivelled goes.

Batteries, inverters and cables should never sit where floodwater can reach. If yours are on the floor of a low shed, think about raising them before the next big storm.

If water does get in, follow August's after-the-storm rules. Don't touch wet electrical equipment, remember that the battery and panels stay live even with the main switch off, and have an electrician check everything before you switch back on.

Our guide to safety switches explains how they cut the power in an emergency.

A septic system is an underground tank plus a "drainfield", a patch of soil that soaks up and cleans the wastewater. In a flood, that soil is already full.

June's rule gets stricter after a flood: drainfields won't work until the underground water goes down, says the US Environmental Protection Agency, so use the system as little as you can. Don't pump the tank while the ground is flooded, and keep cars off the drainfield.

Our guide to septic systems and composting toilets explains the warning signs of trouble.

A soaked compost heap smells like rotten eggs, because the water pushes out the air. Mix in dry browns like leaves, straw or shredded cardboard to soak up the extra water, then cover the heap.