From our perspective as Portulaca plants, often called moss roses or purslane, our relationship with fertilizer is a simple one. We are natives of hot, dry, and often nutrient-poor soils in places like Brazil, Argentina, and Uruguay. Our succulent leaves and stems are designed to store water, and our extensive root systems are highly efficient at scavenging for what little nutrients are available in these lean environments. We are not heavy feeders. In fact, an overabundance of nutrients, particularly nitrogen, can be more detrimental than beneficial to us. It encourages an explosion of weak, leggy green growth at the expense of our greatest pride: our vibrant, prolific blooms. Too much food can literally spoil us.
While we can survive in poor soil, a light and thoughtful feeding regimen can help us truly thrive, especially if we are grown in containers where our root systems are confined and cannot search for nutrients. What we need is not a rich feast, but a gentle, steady snack. A balanced, water-soluble fertilizer with equal parts nitrogen, phosphorus, and potassium (such as a 10-10-10 or 20-20-20 formula) is ideal. More important than the strength is the phosphorus content (the middle number), as this element directly supports strong root development and, crucially, abundant flower production. A half-strength dilution of the recommended dose is always preferable to a full dose for our sensitive systems.
Timing is everything. Our growing season is the warm, sunny part of the year. Please do not fertilize us when we are newly planted or during cool weather; our roots are too tender and cannot absorb it. Wait until we are established and actively growing. A single application of a slow-release fertilizer mixed into the soil at planting time can provide a gentle, continuous supply of nutrients all season long, which is perfect for our low-maintenance nature. Alternatively, if you are using a liquid fertilizer, a monthly feeding is more than sufficient. Begin this schedule about a month after planting and cease all fertilization as the days begin to shorten and cooler temperatures arrive in late summer or early fall. This allows us to naturally harden off and prepare for dormancy.
We will communicate clearly if we are receiving too much fertilizer. Please pay attention to our signals. An overabundance of nitrogen will result in an abundance of lush, green foliage but very few of our characteristic flowers. Our stems may become unusually long, weak, and floppy (etiolated), as they struggle to support the rapid but soft growth. In severe cases, the salt buildup from fertilizers can actually burn our roots, leading to brown, crispy leaf tips, stunted growth, and overall decline. If you see these signs, immediately stop fertilizing and flush the soil with plenty of clean water to dilute and wash away the excess nutrients.
