Too much water means that most or all of the tiny soil pores, which normally hold some oxygen, are filled with water. When roots don't get the oxygen they need, they can't function properly and are more prone to infectious diseases, like root rot. Affected plants lack vigor and may wilt; leaves become yellow. Raised beds can help improve drainage.
A shortage of soil water can stunt plant growth and slow flower and fruit production. Leaves either turn pale and wilt or develop brown,scorched areas. Shallow-rooted annual plants are often most affected. Regular deep irragation can help mildly affected plants recover and prevent future problems. Soaker hoses are an efficient and economical way to give your plants the water they need.
Sudden cold snaps can kill tender buds, growing tips, and other woody plant parts. Leaves turn yellow or drop, buds may drop, stems can crack, and bark may split. Unseasonably low temperatures during the growing season can damage warm-weather vegetables like corn, beans, and tomatoes. Protect actively growing plants with floating row covers or other frost shields. Avoid fertilizing after midsummer; later fertilizing promotes soft growth that is more frost-prone. When the ground is frozen, dry winter winds can pull moisture out of buds and evergreen leaves, causing browning and tip dieback. Protect dormant plants with windbreaks or spray with an antitranspirant to block moisture loss.
Young plants exposed to high temperatures often wilt and may die. Cold-weather vegetables like lettuce and spinach stop producing new leaves and will bolt (go to seed). Shade and water may help plants recover; shade can also help prevent damage. Water well in the early morning and again in the evening if necessary. Avoid planting cool-weather crops that will mature in midsummer. Pull out and compost plants that bolt.
Plants become spindly and are more susceptible to lodging (falling over) when light is inadequate. Green leaves become pale, and variegated or colored leaves may turn evenly green if they don't get enough light. If plants show these symptoms, try moving them to a sunnier spot.
When exposed to direct sunlight, some fruits and leaves develop sunscald, discoloration, or blisters.Too much light can burn the foilage of shadeloving plants, causing brown patches or dead leaves. Plants with purple or yellow leaves often fade or burn in direct sunlight. If you're not sure how much light a
plant needs, see how it grows in partial shade; if it turns pale or spindly, gradually move it into more sunlight. Always place seedlings or young plants in the shade, slowly introducingthem to more light as they grow.
Leaves develop a silvery discoloration and tattered leaf edges when exposed to prolonged high winds. Windblown plants may lose large amounts of water through their foilage, causing leaves to appear wilted. Walls and windbreaks may be the solution.
When nutrients are lacking, plants are less vigorous and yield poorly. Common deficiency symptoms are abnormal leaf color, curled or stunted leaves, and dead growing tips. Regular soil tests can alert you
to developing deficiency problems.
High concentrations of nutrients may cause the same symptoms as nutrient deficiencies. In some cases, the effects of excess nutrients are indirect. Too much nitrogen, for example, often produces lush plants with few flowers or fruit. Soil tests can show you if an imbalance is developing. Follow package directions for fertilizer application rates.
Ozone pollution, from automobile exhaust and other internal combustion engines, causes stippling or yellowing of leaves. Damage is especially severe on the upper leaf surfaces and on leavesthat have just matured.
Under windy conditions, herbicides applies along roadways, in farm fields, or in neighborhood yards may drift over your property and injure your plants. Depending on the product used, leaves may appear burned, bronzed, distorted, or discolored, or plants may die. Protect your plantings with walls, windbreaks, or other barriers.
Late cold snaps can injure flowers and reduce crop yields.