Care of Your Cactus
In most cases cactus will do well in pots as long as you remember three things. Food, light, water.
When you bring the plant home most of the time it is in a small pot and it probably has grown there for a long time, which means it has used up most of all the nutrients in the soil. So think about repotting and setting up feeding program. Most cactus like several small feeding, better than one large feeding. I like a time release type in the spring and this will feed the plant for six or more months. The other way is to give the plants food three time a year (spring, summer, fall)with a dilute solution of plant food like (5-10-5). This should do them well for the year.
A potted cactus will live and flower in the house if given enough light, place the plant near a bright lighted window, where it will receive light most of the day. On the patio is different place the cactus in a partly shaded area until it become accustom to the sun. Never bring the cactus home and place it in the bright sun, cactus sun burn just like people.
Cactus in pots require more care in watering than in the ground. In the growing period which can be spring & summer or fall & winter. Depending on where they come from, south america or north america, the plant should not be allowed to go completely dry, just moist. In the house watering could be as little as once a month depending on the dryness of the house. But outside as much as every two or three days. Take a wooden pencil or dow rod and place it down through the soil to the bottom of the pot, when removed, if damp soil is on it don't water. After a few try's you will learn when to water.
Potting mix for San Antonio area consist of
1 part potting mix (not soil)
1 part washed sand 1 part course gravel or pumas
Care of Your Cactus
Outside Plants in Ground
Only a select few cactus will survive this climate in san antonio, because of our winter rains. In selecting plants for use here one must look at the habitat from which the plant originates. Most of the cactus that grow in texas, and some parts of mexico and even some from south america will survive here. First one must look at how and where to place the cactus. Selecting a location is a good place to start. It must have sun most of the day. Morning and afternoon sun is better than two o clock sun. The area should have very good drainage, if the yard is level you will have to go to above grown beds. I like to make my beds by placing several large rocks in a circle or some odd shape then remove about a foot off dirt from the center , an replace it with a good mix to the top of the rocks. This will assure that the plants will not stand in water. This is more important in the winter than the summer. Most cactus are not killed by the cold, but when the water inside the plant freezes it expands and splits the outer layer of skin, this allows bacteria to enter the plant and kill it. In the winter I listen to the weather report if we are to get rain then a freeze, I will cover my more tender ones with a box or tarp (not plastic) to help keep them dry.
Potting mixes can be made by mixing one part potting mix, one part washed sand & one part course fill (rocks, pumas, broken pots, etc.) Don`t worry too much drainage is better than not enough. Lets talk about shade. Most cactus can use a little protection from the two o'clock sun. A small plant near by or a large rock will work, just a little help. A large rock next to the plant will help hold heat in the winter and will cut down on watering in the summer.
When planting the cactus I never dig a deep hole down in the potting mix. I want the plant to set on top of the potting mix, this allows the roots to go down to get moisture with out the plant setting in wet soil. A lot of time i will use course river gavel around the base of the plant to keep it off the wet soil. After you plant the cactus give it a small amount of water every couple weeks if it doesn't rain, for about a month then let nature take it course. Feed the plants about once a year. With a dilute solution 10-10-10- or a good plant food.
Lets Build a Cactus Garden
Large rocks, potting mix
To start your garden look for a sunny, well-drained area. For a lot of us, this will be hard to do. Our yards are too flat, so we have to build raised beds. I like to build my bed so that there will be no chance of the plants becoming water logged. First draw an outline on the ground of the garden. Don't make it to large, you can always expand. Now take out some of the top soil (6" to 12") deep. Then place a narrow strip of plastic where the rocks will be, let it extend into the hole a few inches, this will help control grass from getting in the garden. Now place the rocks around the hole, don't make it round or square, do a natural look. If the garden is to be facing the street you can go two or three rocks high in the back. Now fill the hole to the top of the rocks with your soil mix. A good cactus mix is: one part potting mix, one part washed sand, and one part large (gravel, pumas, broken clay pots,) most anything that will help keep the soil loose. If the garden is to be level, mound up the mix to make it show better and increase drainage.
Now Lets Plant
Take all your plants and set them in the garden to give you an idea as to where to put them. Dig a small hole in the mix just deep enough to cover the roots, leaving the cactus body on top of the soil. Cactus that are not winter hardy can be used by leaving them in the pot. Just bury the pot so they can be removed and taken in for the winter. Give the plants a small amount of water ever two or three weeks until they root. Then let nature pay the water bill. Feed once a year with a plant food like 10-10-10 or good house plant food. Never overfeed, this is where a little does better. A few large well placed rocks will add protection from the hot sun, and help hold moisture, and it just looks good. Now go build that garden and save water.