Propagating Cacti

If you enjoy growing cacti you will get a great deal of satisfaction from propagating your own plants. It is fairly straightforward as long as you follow the instructions.

growing-cacti

Taking cuttings

The best time to take cuttings is from April until June. Opuntias are ideal as the stems or pads root easily. Alternatively try Echinopsis, Rebutia or Mammillaria –these are cacti which grow in clusters with many offsets. Sever offsets at the place where they meet the main plant. Don’t cut off the top, leaving a cut section attached to the parent plant.

cacti-cuttings

Use well-draining, porous compost for planting. Commercial cactus compost is ideal, but you might have to add a little more washed sharp sand to ensure good drainage.

Give cacti and cuttings dry air. Also give them plenty of light, but not strong sunlight until the roots are growing well. Moisten the soil initially, then water sparingly until roots have fully formed.

Growing from offsets

  • Choose a cactus that produces many offsets: Echinopsis, Rebutia or Mammillaria.
  • Remove offsets with tweezers at the point where they join the parent plant.
  • Allow your cuttings to dry out for 3-4 L days before you plant them. This is done to stop the sap (that is produced at the severed edges) becoming a breeding ground for bacteria.

Growing cacti from seed

It is best to sow cacti seeds early in the year, from late January until late March. You can obtain seeds from a specialist nursery: be sure they are really fresh.

Sow seeds in a good commercial seed compost or cactus compost to which you have added about one-third parts gritty sand. Cover the tray with a piece of glass or place in a polythene bag and put it in a dark warm place with a temperature of about 21°C (70°F). It may only take a few days for the seeds to germinate, but some varieties may take longer. When the seedlings begin to appear, gradually increase the light but do not expose to full sun. Allow air to circulate around the seedlings to prevent damping-off. Keep the compost barely moist and the temperature above 18°C (65°F).

Sowing Seeds

  • Fill the seed tray to within 1.2cm (1/t inches) I of the top. Soak the compost by standing the seed tray in a bowl or tray of shallow water. When the compost is damp, allow it to drain.
  • Sprinkle your seeds evenly and thinly over the surface of the compost. If your seeds are very small, do not cover them. If seeds are larger, cover them to about their depth with fine gritty sand.
  • Once cutting has dried, set it on top of the compost – don’t bury it too deep or it will rot. Give plenty of light but not full sun. Moisten soil initially, then water sparingly until the roots form.
  • After the roots have become well established, treat as a mature plant. The cactus should grow steadily in the first year. Repot only when it has put on good growth and has outgrown its pot.

Grafting cacti

  • Grafting should not be done unless the cactus has difficulty growing on its own rootstock. All cacti look better growing naturally.
  • Never graft when the stock or scion is dormant – always choose the growing period, beween late May until the end of July. This gives times for the union between stock and scion to mature before the dormant period.
  • The idea of grafting is to get the top and base to grow together – they must match in size. Choose only healthy plants that are growing well. Never have the stock too long – it looks unattractive.
  • There are three different methods: the flat graft; side graft; and cleft graft. The best stock for a flat graft are Trichorcereus or Hylocereus. In the side graft the cuts are made at an angle. It is suitable for Aporococtus or Schlumbergera: the best stock is Hylocereus or Selenicereus.
  • For a flat graft, cut straight Make a similar straight cut across base of the scion 2.5cm (1 inch) deep. Prepare the scion by removing the skin from both sides at the base to form a fleshy wedge about 2cm (3/4 inches) long. Insert in the cleft and use a suitable cactus spine to push through both the stock and the scion. The best stock for cleft grafts are Selenicereus and Pereskia.
  • With all grafting, use a very sharp knife and for best results only do the graft on a warm day.
  • Use the cleft graft when you want to form a more tree-like growth for cacti such as Schlumbergera and other slender plants with a hanging growth habit. You will need a longer stock to form the ‘trunk’. Make a straight cut at the top of the stock, then a vertical slit down the centre about Slide scion on to stock so that centres align. Secure with a rubber band. Remove rubber band when two have united. Right: Oriental Moon Cactus grafted on to a Hylocereus.

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