GETTING a steady supply of water for plants isn’t as easy as you might expect during a Scottish spring. April showers followed by a warmer and often drier May usually aren’t enough.

The leaf pores, or stomata, that absorb carbon dioxide from the atmosphere for photosynthesis also release water through evaporation. When more water evaporates than the roots can provide for a plant, the leaves wilt, the stomata close, photosynthesis stops and the plant dies.

Warmer air and an innocuous breeze readily dry out the soil’s surface, making seedlings and young plants especially vulnerable. Directly-sown vegetable seeds and hardy annuals need careful treatment. Among others, these include: cornflowers (Centaurea cyanus), opium poppies (Papaver somniferum) and night scented stocks (Matthiola bicornis). Even dry-loving eschscholzia, Californian poppies, need moist soil to germinate.

So, when direct sowing any seedlings, prepare a drill and water it with a fine rose before, not after, sowing. This approach also applies to small potted plants: water the hole, then plant. As a result, seeds and roots are in direct contact with moisture and the covering soil acts like a mulch that reduces evaporation.

But as the tiny root systems are so close to the soil surface, seedlings in particular mustn’t be allowed to dry out. Frequent watering with a fine rose is essential.

Early morning and evening watering lets the ground stay moist longer, giving small plants a better chance to absorb it. But wet ground is irresistible to the night’s emerging mollusc brigade, so there’s much to be said for a morning rather than evening shower.

At this early stage of a plant’s growth, you only need to focus on watering the top 7-10cm. But, as the root system develops, keep one step ahead of the roots by keeping deeper soil moist as well, otherwise the roots stay near the surface and don’t develop an extensive system.

As plants grow larger we should aim to give the soil a good soak once a week, rather than a daily dribble. If you don’t have time to water everywhere at once, do one section most evenings, so each plot is thoroughly watered over the seven-day period.

The watering regime depends firstly on your type of garden soil. If thin and gritty, water pours straight through, but crumbly and well-structured soil readily retains moisture. Try improving poor soil by adding bulky material, such as well-rotted muck, leafmould or compost. This could take a few years to have an effect and you’ll have to spend a lot more time watering in the meantime.

Where planting permits, mulching is useful. This conserves moisture by preventing evaporation and cuts down on the weeds that compete for the moisture. After thoroughly soaking the ground, cover with a layer of organic matter, preferably to a depth of 5-10cm. As well as muck, leafmould or compost, you could use forest bark or wood chip.

Whatever your technique, aim to water the soil, not the foliage. As well as being a waste of good water, it may encourage fungal disorders in some plant species. So, a soaker hose system, laid on or below the soil surface, is much more effective than overhead sprinklers.

There’s a wide selection of soaker hose systems available online. Porous pipes can be connected to a water butt or a mains supply, if turned on very slightly. This can be a worthwhile and fairly inexpensive investment.

Each of my vegetable beds is kitted out with cheap and cheerful leaky hose that’s connected to my spring overflow pipe. They all get a good 24-hour soak once a week, from now until harvest.

At this time of year, when plants in veg or ornamental beds are small, there should be space between the plants, so it’s easy to aim a watering can or hose on to the ground rather than foliage. When the plants have fully grown, remove the rose, and water carefully between them.