Opuntia Cactus Damage and Not Growing

Q. Two out of three of our beaver tail cactus clumps have multiple dying paddles. We don't fertilize the cactus and all three are watered the same, extreme heat, every 1.5 weeks; moderate heat, every 2-3 weeks, and nothing in winter. All receive approximately 1.5 gal. each time and all are on mounds that drain.  

Freezing damage to beavertail (Opuntia) cactus

A. If I were only shown your pictures with no explanation I would have come to two conclusions: freezing damage from previous winters because damage to the edges of the paddles, no soil improvement combined with watering, and poor growth due to a lack of nitrogen fertilizer.

Light freezing damage to nopal (Opuntia) cactus on the edge of the pad and regrowth in the spring from nondamaged areas.

            Most of the damage to the pads are environmental in nature. The condition of the pads can be improved with a change in soil amendments, watering and applying fertilizers. They like soil improvement at the time of planting. If they are watered too often they will die.

            When I plant beaver tail cactus from a single pad it is during the heat of the summer, not the fall or winter months. I amend the soil with either compost or manure before planting. I use about a 50/50 mix in the soil.

Planting a single pad of nopal cactus. Moisture meter used to make sure soil is not too wet for next irrigation in about three weeks.

            I'm glad to hear they are planted on a mound if drainage is a problem but I usually plant them on level ground as long as the soil is amended at the time of planting. Amending the soil does two things besides providing nutrients; it holds water in the soil but at the same time improves drainage. This can be difficult to accept but this is the magic of soil amendments used in our very poor soils.

Nopal cactus planted in an irrigated bed with compost applied on top of the soil. Not the best way of using compost. It is better if the compost is mixed with the soil at the time of planting.

            I harvest mature pads at their "joint" or nodes making sure I do not damage the pad I am harvesting and do not leave any traces from the mother pad. The joint or node is smooth and not raggedy.

Nopal pads are harvested at the "joint" or where the harvested pad is joined to the mother pad

            Harvesting a pad can be done most easily by grasping the pad with newspaper and bending the pad almost to the point of splitting through the joint. Then lightly touch this joint with a very sharp, sanitized knife.

            When done this way, the harvested pad separates easily and quickly from the mother pad right at the joint. If it doesn’t and the joint is “raggedy”, then trim it being careful not to cut into the harvested pad.

There should be no remnant of the harvested pad remaining on the mother pad. Remove it.

            Remember, this is done in the early summer, not in the fall or winter. Put the pad in the shade for three days to a week, oriented either upright or turn the pad over daily to keep it from curving. The pad will continue to grow after harvesting so keeping the pad from curving is important at planting time.

If you leave the pad lying on its side for even a day it continues to grow and curves the pad making it very difficult to plant or sell.

            The other option is to dip or dust the cut end of the pad in a fungicide such as a copper fungicide. The pad is planted in the amended soil upright so that the edges are oriented north to south. This gives an equal opportunity for one side of the pad to receive morning sun and the other side of the pad to receive afternoon sun.

Mature harvested pad healed, dipped in copper based fungicide and ready to plant. Wont qualify for "organic" but it helps prevent pad losses after planting due to overwatering or poor soil drainage.

            Once planted, water deeply every three weeks during the summer, not more often than this. To do this, put a basin around the planted pad about 2 feet in diameter to hold the irrigation water. Fill the basin with 2 to 3 inches of water and let it drain into the soil.

Commercially harvested nopal pads for green vegetable

   

I like to harvest them much younger when they are more tender for personal use

         The next irrigation in the same way is three weeks later. If you water more often than this the cactus can become so large, so quickly, there is a danger it will fall over because the roots are not large enough to support the top.

            Planting and watering a single cactus pad should get the new cactus 3 feet tall in one growing season. Once the cactus is the size you desire, water less often and remove pads if it gets too tall.

            Once the cactus is established, fertilize them once a year. If pads and height are desired, use a high nitrogen fertilizer. Once the cactus has the size you desire, switch to a low nitrogen fertilizer such as the kind you use for roses or growing tomatoes.

From a single pad your cactus should be at least this tall in the first season if managed correctly

            In addressing your questions, I would not do anything to your cactus until next March or April. At this time I would prepare a new hole, the soil amended with compost, and plant some harvested mature pads, as free from blemishes as possible, in these locations. I did not see anything that looked like a disease or insect problem. However, to be on the safe side I would spray the pads with an alcohol spray or soap and water mixture before planting. The fungicide you are suggesting, I don't think there is a role for it unless you see some soft rotting occurring somewhere on the roots or the pads.