There are anumber of pests and diseases that cacti can be affected by, and without the details it is hard to tell. Usually, problems are caused by overwatering, lack of sun, low temperatures and a variety of pests.
To help you work out what the problem might be, check the Web Links to the left for more information.
This depends on the type, but if it is a round (ball) cactus or a tall (columnar) cactus, you would water it every 2 to 3 weeks. If it is a Christmas cactus, an Easter cactus or an Epiphyllum, water it every 2 weeks. Both types like bright light. Do not put them in direct sunlight. A warm, south facing window is good for the ball and columnar cactus. A slightly cooler room is better for the other types.
Particular cactus care and cactus needs depend upon the plant's native environment. A desert cactus is used to higher levels of heat and light, and lower levels of moisture and vegetative competition. A jungle cactus is used to lower levels of light; and higher levels of heat, moisture, and vegetative competition.
But that doesn't mean that cactus plants must be subjected to the extreme, harsh conditions that characterize their native desert or jungle environments. They tend to respond well to free draining soil that holds some water, without waterlogging. They tend to prefer regular fertilizing and watering, every 10-14 days, during their growing seasons; and none during dormancy. They tend to like protection from widely ranging temperature, moisture and lightextremes. They tend to handle repotting every couple of years if they're in containers.
This depends on the type, but if it is a round (ball) cactus or a tall (columnar) cactus, you would water it every 2 to 3 weeks. If it is a Christmas cactus, an Easter cactus or an Epiphyllum, water it every 2 weeks. Both types like bright light. Do not put them in direct sunlight. A warm, south facing window is good for the ball and columnar cactus. A slightly cooler room is better for the other types.
A small cactus is taken care of in the same way as a larger cactus plant, but on a smaller scale. It's particularly important to monitor levels of heat, light, and moisture; and degrees of competition from other vegetation. Especially important is care against excessive watering, lighting and chilling. Also important is repotting every couple years, into pots that aren't much wider than the plant's width. The general rule is a pot 1 inch/2.5 centimeters and 2-4 inches/5-10 centimeters wider than a plant that's respectively less or more than 6 inches/15 centimeters across.
The vacuole stores water and nutrients that help keep the cactus alive.
because it helps bring precipitation to the cactus...
Pear Cactus is used to help with diabetes, but no studies prove that Pear Cactus will cure diabetes.
As a cactus is a form of a plant, it will require sunlight for photosynthesis and water to stop it from drying out and to help the cactus plant grow.
the leaves of a cactus help get the suns nutrition foe the plant to grow None pretty much and formally proper cactus have no leaves only it's convergently evolved cousins do.
A cactus' waxy skin helps it retain moisture in desert climates.
it absorbs more water
Flowers help cactus plants survive in the desert by attracting pollinators. Because of pollination, the cactus plants may have fruits full of seeds. For example, the giant saguaro cactus [Carnegiea gigantea] depends upon bats for pollination of its huge, light colored bat blossoms.
Well You Could But It May Not Be Very Good For You You Might Get Sick
Spines: Spines help the cactus in several ways. The most obvious use of the spines is for protection against foragers. The cactus basically states "How much pain are you willing to indure to get a drink in this desert?"; Surprisingly, some animals do partake. In some cactus varieties the spines participate in water collection. Water from dew condenses on spines and, in some cactus species, downward-pointing spines help to direct rainwater to the roots of the plant. Spines help to reflect light away from the cactus stem theoretically lowering the stem temperature. Some spines also trap in a layer of air next to the cactus stem preventing loss of water via evaporative cooling.
The stem of a cactus is able to store water during rainy periods for use during a drought.
Prickly Pear Cactus fruit