Epsom Salt for Christmas Cactus – When and How to Use

Epsom salt can be a beneficial supplement for Christmas cacti because of its magnesium and sulfate content. Magnesium gives leaves a green color and activates important enzymes for growth. However, it’s important to follow proper guidelines when applying Epsom salt.

Feertlize the Christmas cactus with Epsom salt mixed at 1 teaspoon per gallon of water monthly from when new growth starts in spring and throughout the summer, but not the same week you applied regular fertilizer.

You can get Epsom salt here on Amazon as an early preparation for the growth season. Using it correctly will promote healthy foliage, faster growth, and more blooming. Epsom salt should not be applied in fall and winter.

Epsom Salt for Christmas cactus – Benefits

Every plant needs nutrients to thrive. Nitrogen, potassium, and phosphorous are the primary nutrients needed in large quantities. Plants also need moderate quantities of magnesium, Sulfur, and calcium, hence classified as secondary nutrients.

Epsom salt (magnesium sulfate) is a key element of the chlorophyll molecule. Chlorophyll gives plants their green color and helps them absorb sunlight for making food through photosynthesis.

Unlike many plants, the Christmas cactus has higher requirements for magnesium. If you haven’t used Epsom salt, yellow spots on your Christmas cactus might be a telltale sign of declining magnesium levels.

Epsom salt is a great source of magnesium, and it comes with the following benefits for a Christmas cactus:

  • It enhances the appearance of a Christmas cactus by making it greener.
  • It helps the plant trap more light for maximum food production, thus, healthy growth.
  • Healthy foliage translates to generous blooming, thus more flowers during winter holidays.
  • Magnesium makes a plant hardy and tolerant to diseases and pests.

Over time, magnesium leach out of soils from watering or rainfall. Deficiency is common in old potting soils, acidic soil conditions, and soils with excessively high potassium levels. It’s, therefore, very important to keep replenishing your soil.

When and How to Use Epsom Salt on Christmas Cactus

When flowers completely fade, typically in early spring, a Christmas cactus will enter an active growth period until the end of summer. New growth will start forming on the stems as the plant expands.

This is the right time to feed your Christmas cactus to enhance more growth and prepare it for future blooming.

In addition to the regular fertilizer (20-20-20 or 10-10-10 diluted to half strength), fertilize with Epsom salt (magnesium sulfate) mixed at 1 teaspoon per gallon of water monthly but not the same week you applied the fertilizer.

Many Gardeners also incorporate homemade fertilizers like compost or coffee grounds. Using them in small quantities isn’t bad, as they improve soil tilth and structure. A tablespoon or two well spread into a thin layer should be enough for a month.

The Christmas cactus doesn’t need any fertilizer while it is blooming. Fertilizing when buds have formed can result in flowers or buds falling off. Also, excess nitrogen fertilizer makes the plant weak to bear blooms.

For a Christmas cactus to bloom, it needs some period of rest. When fall arrives, do not feed the plant; cut back on watering and place it in uninterrupted darkness for 12 to 14 hours daily for six to eight weeks.

Cool temperatures and short daylight episodes will make the Christmas cactus bloom profusely.

Additional care requirements

Christmas cactus prefers bright indirect sunlight; therefore, place it on a north or eat-facing window except when you are forcing the formation of flower buds in mid-October to December.

Growth increases when daytime temperatures are between 70 and 80 degrees Fahrenheit and night temperatures are between 55 and 65 degrees.

Unlike other desert cactuses that are tolerant to drought, the Christmas cactus need constant moisture to thrive but not waterlogged soil. Christmas cactus root rot is a fatal condition caused by overwatering.

Watering the cactus only when the top inch of the soil feels dry to the touch. Additionally, place the plant on a pebble tray half filled with water to boost humidity levels in dry air environments.

When flowers have completely faded, prune your Christmas cactus. Removing a few stem sections encourages branching and growth. You may root the cut segments to produce more plants you can gift your friends and family.

Although Christmas cacti like to be root bound, the rootball may eventually outgrow the pot. It forces the roots to entangle and stop taking up water and nutrients as needed. You’ll have to repot the Christmas cactus in a slightly bigger pot after every two years to avoid this problem.

Final Thought

Fertilizing a Christmas cactus during its active growth is important for growth and flower production. Apart from the monthly application of regular fertilizer, apply Epsom salt to provide magnesium.


  1. University of Minnesota Extension: Magnesium for crop production
  2. The Royal Horticultural Society: Nutrient Deficiencies
  3. North Carolina Cooperative Extension: Christmas Cactus Care

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