Plant Care Royal Cross

Royal Cross

Also known as

Silver Arrows, Silver Arrows, Silver Arrow, Silver Arrows Cactus and Royal Cross Mammillaria


Mammillaria karwinskiana

How to care for Royal Cross


How often to water your Royal Cross

Water needs for Royal Cross
0.5 cups
every 12

Royal Cross needs 0.5 cups of water every 12 when it doesn’t get direct sunlight and is potted in a 5" pot.

Use our water calculator to personalize watering recommendations to your environment or download Greg for more advanced recommendations for all of your plants.

Calculate water needs of Royal Cross

Water 0.5 cups every

Does your plant get direct sunlight?

Select the pot size


Check the growing potential in your area

A plant's growing potential is determined from its location, the time of year, and current local weather.

Select a city to check sunlight intensity

Finding light for Silver Arrows in your home

Light needs and placement for plant Royal Cross: 1ft from a window
1ft or less from
a window

Royal Cross love being close to bright, sunny windows 😎.

Place it less than 1ft from a south-facing window to maximize the potential for growth.

Royal Cross does not tolerate low-light 🚫.

Select your region to see how the current weather in your area affects the placement of Royal Cross in your home 🏡.


How to fertilize Royal Cross

Nutrient, fertilizer, and repotting needs for Royal Cross: repot after 2X growth

Most potting soils come with ample nutrients which plants use to produce new growth.

By the time your plant has depleted the nutrients in its soil it’s likely grown enough to need a larger pot anyway.

To replenish this plant's nutrients, repot your Royal Cross after it doubles in size or once a year—whichever comes first.

Water Needs
Sunlight Needs
Native Region

Care Summary for Royal Cross

Royal Cross

Royal Cross

Greg recommends:


0.5 cups every 12 days


< 1ft from a window


Repot after 2x growth

Based on the 4” pot your plant is in, and that it doesn’t get direct sunlight.

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