Weather Effects
Plants and Soil

Temperature, rainfall, humidity, and wind, alone or in combination, affect both plants and soil in your garden. Once you get to know the changes and extremes of local weather, you will be able to choose plants that flourish in those conditions, as many plants will withstand extreme heat or exposed situations. Weather changes with the seasons and from year to year, so there may always be times when you need to protect your plants from severe conditions. Plants are often described according to their ability to withstand cold – their hardiness. Use this as a guide to where to plant, positioning more tender plants in a sheltered spot or in pots that can easily be moved under cover in winder. A garden planned and planted to suit the local climate is much easier to care for and will look healthier than one planted with no regard to the weather.

Frost, Cold and Snow

Frost can injure even relatively hardy plants, freezing and killing plant tissues, especially in late spring and early autumn. All half-hardy and tender plants are vulnerable, as are young growth and blossoms on otherwise hardy plants. As decreasing temperatures freeze the soil progressively deeper through winter, surface roots may be injured, and entire root balls of plants in pots may be killed. Alternate freezing and thawing of the soil is also damaging often causing small, newly set plants to heave out of the ground. Snow helps insulate roots and low-growing plants, but its weight can cause branches to break and can permanently damage the shape of conifers.

Plant Hardiness

Hardy Plant: One that normally survives the average minimum winter temperatures in a given area without the need for extra protection.

Half-Hardy Plant: One that undependably survives normal winter conditions. To guarantee its survival over winter it should be protected outside or brought undercover.

Tender Plant: One that is normally damaged or killed in winter. Bring under cover or provide winter protection.

Wind

Some air movement is needed to reduce humidity and lower air temperatures; it also keeps many diseases at bay, and helps to disperse pollen. However, excessive wind can scorch foliage and flowers, distort growth, and may even break or uproot plants, as well as dry out soil. Salt-laden coastal winds can cause severe scorching, and salt from sea spray can kill plants if it reaches their root systems. In windy conditions, spraying against pests and diseases is difficult. Fewer fruits may set since pollinating insects are less active.

A windy site can usually be planted successfully behind a living or artificial windbreak, this must allow about 50 percent of the wind to blow through to be most effective.See "Wind Tunnels".

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