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Common growing problems

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Star-flowered false Solomon's seal
Photo: Jardin botanique de Montréal (Michel Tremblay)
Maianthemum stellatum

So you’ve decided to plant native plants in your garden! Congratulations!
You can take advantage of the Great Gardening Weekend at the Jardin botanique
on May 24-26, 2024 to get expert advice on the topic.

Attend gardening workshops, meet the experts,
and choose from a wide range of native plants.
All in one place!

Lack of light

Symptoms

  • New shoots are weak looking.
  • Growth is slow.
  • New leaves are smaller and turn pale.
  • Older leaves may turn yellow and fall.
  • Brightly coloured leaves turn green.
  • Plant fails to bloom.

Solution

  • Increase artificial or natural lighting at first signs of weakness.
  • Reduce room temperature by about 3°C.
  • Water less frequently and do not ferttilize.

Too much light

Symptoms

  • Leaves exposed to direct sunlight turn pale and develop faded spots that turn dry and brown.
  • Affected leaves turn increasingly pale.

Solution

  • Remove plant from direct sunlight in summer or install sheer curtains to filter light.
  • Remove badly damaged leaves.

Lack of water

Symptoms

  • Leaves wilt.
  • Growth is slow.
  • Brown spots appear on margins of older leaves, which eventually turn yellow and fall.
  • Soil is pale, hard and dry on the surface or damp on the surface and dry farther down.

Solution

  • Water plant.
  • If soil does not absorb water, immerse pot in a bucket of water until air bubbles stop appearing.
  • Remove pot from water and allow it to drain.
  • Continue watering at normal intervals.

Too much water or poor drainage

Symptoms

  • Leaves wilt.
  • Growth is slow.
  • Brown spots appear on leaf tips.
  • New and older leaves eventually turn yellow and fall at the same time.
  • Soil is constantly damp or drainage is too slow.
  • Roots become spongy, turn brown and rot.

Solution

  • Make sure that no water remains in saucer and place pot on a stack of newspaper for about one hour.
  • Return pot to saucer and allow soil to dry out before next watering.
  • Water less frequently.

Too much heat

Symptoms

  • Stems grow long and lanky (despite proper lighting).
  • Older leaves wilt (despite proper watering), turn brown around margins and fall.

Solution

  • Remove plant from direct sunlight in summer or heat sources in winter.
  • Check to see whether plant requires a rest period.
  • Remove badly damaged leaves to avoid disease.

Drop in temperature

Symptoms

  • Leaves are covered in white spots or turn yellow and drop a few hours after a sudden change in temperature.

Solution

  • Few indoor plants tolerate temperatures lower than10°C.
  • Keep an eye on plants kept outdoors in summer and protect plants transported outdoors in winter.

Lack of fertilizer

Symptoms

  • Young shoots are weak, smaller and paler (although not yellow) than rest of plant.
  • Flowers are faded or plant fails to bloom.
  • Plant is in an artificial potting mix and was not fertilized during the growing period.

Solution

  • Fertilize as recommended.
  • Transfer to a larger pot and add new soil, as necessary.

Too much fertilizer

Symptoms

  • Leaves turn brown and fall.
  • Plant stops growing.
  • Young shoots are sometimes deformed and blackened.
  • White crust forms on soil surface or pot rim.

Solution

  • Leach excess fertilizer salts from soil by flushing with water several times.
  • Fertilize less frequently and in smaller doses.

Salts accumulating in potting soil because of alkaline water

Symptoms

  • Leaf margins (especially on broad-leafed plants) or tips (especially on narrow-leafed plants) turn brown and fall.
  • White crust forms on soil surface or pot rim.

Solution

  • Let tap water sit for 24 hours before watering plants.
  • Mist aerial parts regularly.

Lack of humidity

Symptoms

  • Leaf tips turn brown.
  • Leaf margins turn yellow.
  • Flower buds dry out and fall.

Solution

  • Use a humidifier.
  • Mist plants regularly.
  • Remove them from heat sources.

Water used for watering is too cold

Symptoms

  • Small pale brown spots appear on leaves.

Solution

  • Some plants are very sensitive to sudden changes in temperature.
  • Use tepid water when watering.
  • Cold water may spot the leaves and slow the growth of some tropical plants.

Pot too small

Symptoms

  • New leaves are smaller.
  • Older leaves turn yellow and fall.
  • Plant wilts quickly between waterings.
  • Roots grow out of drainage holes or show near soil surface.

Solution

  • Confirm diagnosis by removing plant from pot.
  • Repot if roots form a tight ball.

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