For once, this summer the problem for gardeners is too little rather than too much water.

The symptoms of drought stress are well-known: curling, shrivelling, browning leaves that fall off prematurely; stunted growth; poor flowering or fruiting; and, very possibly, death. And to make matters worse, pests and diseases put the boot in and attack weak or sickly plants.

Unfortunately, most garden plants have little resistance to drought conditions because they're not adapted to them. On the other hand, cacti have long, horizontal, fibrous roots that simply shut down during dry spells and the leaves of succulents - such as sedums - or the stems of cacti can store water for months. Some trees growing in east African savannas have developed thick trunks that can store up to 25,000 gallons of water.

Back to Scotland, though. If only I had been wise enough to prepare for hot, dry conditions, had set up my foolproof watering systems and mulched extensively to prevent evaporation. I freely admit that, after so many recent dreary summers, I didn't devote the time to these jobs.

As the drier conditions set in, I presumptuously thought such acts would persuade the jet stream to change course and expose Scotland to relentless attack from Atlantic fronts. If I had dusted off my leaky hoses, my early peas wouldn't have been plastered in powdery mildew and the later ones would have grown to twice their present size, producing a much larger crop.

We all have our sorry tales to tell - a much-loved plant that's on the point of death or flowers that hardly came or were over all too quickly. My glorious delphiniums were the worst they've been for years. Other plants, such as lettuce, spinach, the onion family and cauliflowers, may respond to drought by bolting, running to seed prematurely. This can also happen when a wet spell follows a period of drought, so a return to more normal Scottish conditions isn't without its problems either.

The question is what to do now. If you can now use your replenished water butts, be careful not to overdo it. Plants need moisture, not drowning. Soggy soil stresses roots as they'll be unable to absorb vital oxygen from the soil, so overwatering can worsen the situation. When you're watering pots, remember to do so gradually. A blast of water will rush straight through and scarcely touch the roots. It's much better to water a group of pots together, returning several times to each container. This lets the compost gradually absorb the liquid.

You can help plants fight off pests and diseases by adding a splash of liquid seaweed to the watering can and dowsing the foliage.

Weeding is especially important now. As with all plants, weeds have been growing more slowly, but they do absorb what little water there is. Luckily, hoeing is easy in dry conditions, so weeding can be done swiftly.

It's sometimes suggested that you should cut the stems of stressed plants back by one third to reduce the growth that roots have to sustain. This may help and is certainly true for transplants, but pruning can also cause stress in the short term and much less photosynthesis is taking place. With shrubs and trees, it's better to cut out dead and dying twigs and branches during a drought.

Continue the tidy-up once more normal conditions return. When the soil has become moist, apply a seaweed meal and/or phosphorus-rich fertiliser, such as Agrafeed R. You help the plants by encouraging strong root growth. Once the rains have washed the feed into the soil, cover it with a fresh organic mulch to conserve moisture and, of course, prevent weed growth.

On the bright side, at least the hot, dry weather has kept slugs at bay.