A cactus in the ground cannot be moved out of rain or frost, so choose the spot with care. These steps are for a cactus that already has roots, in a pot or bare-root (with no soil on its roots). For an unrooted cutting, start with how to root a cactus cutting.
The short version
- Plant in the ground if your nights reach 28 to 30 F only now and then. In colder winters, use a pot you can move.
- Choose an open, sunny spot where water never collects after rain.
- Test the drainage: fill a 12 inch deep hole with water, let it drain, refill it and measure the drop over 15 minutes. At 1/4 inch or more (1 inch an hour), plant at ground level. At less, plant on a mound of faster-draining soil or choose another spot.
- Plant in spring or early summer.
- Dig a wide, shallow hole and set the plant at the depth it grew at before, with no green stem below the soil.
- At ground level, fill the hole with the soil you dug out and add nothing. On a mound, fill with the mound soil.
- Wait a week, then water every 2 weeks while nights are above 60 F. Stop when they fall below 60 F.
- Shade the plant with 30% shade cloth until you see new growth at the tip.
Is your climate right for it?
For San Pedro (a Trichocereus) and other tall, ribbed, column-shaped cacti like it, start protecting at 28 to 30 F, earlier for pots and in wet winters. Protecting a plant in the ground means covering it for the night.
- Your coldest nights reach that range only now and then. Plant in the ground and cover the plant on those nights.
- Your winters are regularly colder than that, or stay below freezing through the day. Keep the plant in a pot you can move under cover.
Rot is most likely in wet soil during cool weather, so where most of your rain falls in winter, plant only in a spot that passes the drainage test below. See growing cactus for your conditions.
Choosing the spot
- Sunny and open. Cacti need strong light. Many take direct sun for most of the day once they are used to it, and in hot desert climates many do better with some afternoon shade, such as the east side of a wall or tree.
- Never where water collects. If rain puddles in a spot, do not plant a cactus there, even on a mound. A slope or the top of a rise drains faster, and low ground is a poor place for a plant that is sensitive to frost.
Test the drainage
A cactus needs soil that drains fast. Sandy, silty and gravelly soils usually do, and clay usually does not.
- Dig a hole at least 12 inches deep and 4 to 12 inches wide.
- Fill it with water and let it drain completely. That can take minutes or a whole day.
- As soon as it is empty, refill it. Measure the water depth with a ruler, wait 15 minutes and measure again. Multiply the drop by 4 to get inches per hour.
1 inch an hour or more (a drop of 1/4 inch or more in 15 minutes). Plant at ground level.
Less than 1 inch an hour. The soil drains poorly. Do not plant at ground level here. Either:
- Build a mound. Heap sandy or gravelly soil that drains faster than yours over the spot, higher than the ground around it and wide enough to hold the roots spread out, and plant into the top.
- If you have no faster-draining soil, do not plant here. Test another spot, or keep the plant in a pot.
Planting
When. Spring and early summer give the quickest start. Midsummer adds sunburn risk, and roots grow slowly in cool weather.
Note which way the plant faces. A side that has grown away from the sun may burn if it is turned toward it. Before you take a plant out of its pot, tie a string around the stem with the knot on the south side. A plant that arrived in a box has no south side you can know. Plant it facing any way. The shade cloth described below protects every side while it adjusts.
Prepare the roots. Wear cactus gloves, and loop a length of rope or old garden hose around the stem to move the plant. Do not lift it by its roots. If the potting mix is different from your soil, shake it off so the roots go into your own soil. Trim any broken or frayed roots with one clean cut from a sharp blade. If you cut any, leave the plant in a dry, shaded place until the cut ends are dry to the touch.
Dig wide and shallow. Make the hole as wide as the spread roots and only as deep as they are.
Set the depth. Plant the stem at the depth it grew at before. On a potted plant, that is the soil line in the pot, so note it before you shake the mix off. On a bare-root plant, put the soil surface where the roots end and the stem begins. No green stem goes below the soil, because buried stem is prone to rot.
Fill the hole. At ground level, use the soil you dug out, with no compost, potting mix or sand added. On a mound, use the mound soil. Push the soil under and around the roots with a blunt tool, such as a shovel handle, so no hollows are left. Finish with a thin layer of gravel.
Bracing a tall plant
If a tall plant leans or will not stand at the correct depth, brace it. Do not plant it deeper. Set 3 wooden braces around the stem, each with soft ties or padded with carpet where it touches the plant, and leave them until new roots hold the plant upright. On a large plant that can take several years.
Watering in
Wait a week before the first watering, so any roots damaged in the move can dry.
After that, check the night temperature:
- Nights above 60 F. Water about every 2 weeks. Before each watering, feel the soil 2 to 3 inches down. If it is damp at all, from rain or from the last watering, wait until it is dry.
- Nights below 60 F. Do not water. The one exception is a newly planted cactus in a dry spell: if 2 to 4 weeks pass with no rain, water it once.
Wet the soil around the roots and stop before water stands on the surface. Saturated soil encourages rot and lets a tall plant topple.
Keep to this until you see new growth at the tip, the sign that the roots have taken hold. From then on, follow watering cactus.
The first summer
A newly planted cactus can sunburn in a spot that will suit it later. Drape shade cloth over it, a fabric rated by the share of sunlight it blocks. Use one that blocks no more than 30%. Leave it on until you see new growth at the tip, which generally takes several weeks.
Sunburn turns the skin yellow. If you see yellowing after the cloth comes off, put it back, and see acclimating a cactus to sun.
Torch cactus hybrids (clumping Trichocereus hybrids grown for their flowers) often do better in the ground than in a pot. In hot desert climates they need afternoon shade for their whole first summer.
The first winter
The 60 F rule above carries into winter: once fall nights stay below 60 F, routine watering stops and the plant goes into the cold dry.
Keep the gravel around the base, and keep bark and leaves off the stem. Mulch against the stem holds moisture there that you don't want.
Have a cover such as a cotton sheet ready before the first night near 30 F. See winter care for cactus.
If the stem turns soft, dark or wet at the soil line, stop watering and see cactus rot. If you are unsure what you are seeing, email us with photos at support@thoughtfulpricks.com.
Sources
How to Transplant a Cactus. Michael Chamberland and Jack Kelly, University of Arizona Cooperative Extension, 2020. https://extension.arizona.edu/publication/how-transplant-cactus
Problems and Pests of Agave, Aloe, Cactus and Yucca. Jack Kelly and Mary W. Olsen, University of Arizona Cooperative Extension, revised 2011. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1399.pdf
Cactus, Agave, Yucca and Ocotillo. Jack Kelly and Rob Grumbles, University of Arizona Cooperative Extension, 2009. https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1225.pdf
Testing and Improving Soil Drainage. Aaron Steil, Iowa State University Extension and Outreach, 2024. https://yardandgarden.extension.iastate.edu/how-to/testing-and-improving-soil-drainage
Succulents. UC Master Gardener Program of Sonoma County, University of California Agriculture and Natural Resources. https://ucanr.edu/site/mg-sonoma/succulents
Winter-hardy Cacti. PlantTalk Colorado 1028, Colorado State University Extension. https://planttalk.colostate.edu/topics/annuals-perennials/1028-winter-hardy-cacti/
Plant Care Information: Torch Cacti, Trichocereus hybrids. Arizona-Sonora Desert Museum. https://desertmuseum.org/visit/sheets/TrichoX.pdf