How to Grow Irises From Seed in 5 Simple Steps

When you think of growing irises, you probably picture dividing rhizomes or planting new ones. Growing these stunning flowers from seed is not commonly discussed, but it’s certainly possible, and the results are well worth the effort.

Growing irises from seed allows you to experiment with different varieties, potentially creating unique hybrids that you won’t find in any garden center. It’s also incredibly economical—a packet of seeds costs far less than established plants, giving you dozens of potential irises for the price of one mature plant.

If you’re looking for an interesting winter project or want to expand your iris collection without breaking the bank, growing from seed is the perfect solution. The process isn’t difficult, but it does require patience, as iris seedlings can take several years to flower. But don’t let that discourage you—the anticipation is part of the fun.

Why Grow Iris From Seed

Most gardeners grow irises by dividing established plants or planting rhizomes. These methods are certainly faster, with new plants flowering in their first or second season. So why would you choose to start from seed instead?

Growing irises from seed allows you to participate in the complete lifecycle of these fascinating plants. There’s something magical about watching a tiny seed transform into a seedling, then into a mature plant, and finally produce the iconic blooms that make irises so beloved.

The most compelling benefit of growing irises from seed is the opportunity to create something truly unique. Each seed is genetically distinct, potentially offering new color combinations, patterns, or plant characteristics that differ from the parent plants. For those who love the surprise element of gardening, nothing beats the anticipation of waiting to see what your seedlings will become.

From an economic standpoint, growing from seed is more affordable than purchasing mature plants. A single plant can produce dozens for the same price as one or two established rhizomes. If you’re planning a large iris display, starting from seed can save you a considerable amount of money, though you’ll need to factor in the waiting time.

For those who want to expand their gardening skills, growing irises from seed provides an opportunity to learn about plant genetics, cross-pollination, and seed stratification. It’s a more advanced gardening technique that builds on your existing knowledge and introduces new concepts that you can apply to other plants in your garden.

The Drawbacks

The main drawback to growing irises from seed is the time investment required. Depending on the variety, iris seedlings may take anywhere from two to five years to flower. For gardeners accustomed to quick results, this lengthy growing period can be frustrating.

Irises grown from seed also won’t come true to the parent plant if they’re hybrids. If you collect seeds from a particularly stunning iris in your garden, the seedlings may produce flowers in completely different colors or patterns. This unpredictability can be exciting for some gardeners but disappointing for others who want to reproduce a specific variety exactly.

The germination rate for iris seeds can also be inconsistent, varying greatly depending on the species and the freshness of the seeds. Some varieties may have germination rates as low as 30%, which means you’ll need to sow more seeds than the number of plants you ultimately want to grow.

Finally, iris seedlings require more attention and care than established plants. They need consistent moisture, protection from extreme weather, and regular monitoring for the first year or two. If you’re not prepared for this level of care, you might be better off purchasing mature rhizomes.

What You’ll Need

Before you begin your iris seed-growing adventure, gather these essential supplies:

• Small pots or seed trays with drainage holes
• Seed starting mix or a blend of equal parts potting soil, perlite, and vermiculite
• Clear plastic bags or humidity domes
• Plant labels or markers

If you’re collecting seeds from your own garden, you’ll also need paper envelopes to store the seeds after harvesting, if you’re not planting immediately. For those purchasing seeds, look for reputable suppliers who specialize in irises to ensure good germination rates and authentic varieties.

The soil mix is particularly important for successful germination. Irises prefer well-draining soil, so avoid using garden soil, which can become compacted over time. Creating a mix with both moisture-retaining components (potting soil, perlite, leaf mold) and drainage-enhancing elements (perlite) provides the perfect balance for young iris seedlings.

For those living in colder climates, a grow light setup might also be beneficial, especially if you’re starting seeds when natural light is limited. While not absolutely necessary, grow lights will help produce stronger, healthier seedlings that are less likely to become leggy.

How to Grow Irises From Seed

Growing irises from seed is a rewarding process that anyone can master with a little patience. The key is understanding the steps and providing the right conditions for germination and growth.

Let’s break it down into five simple steps that will take you from seed to seedling.

Step 1: Harvest

If you’re collecting seeds from your own iris plants, timing is everything. Allow the iris seed pods to fully mature on the plant—they should turn brown and begin to split open naturally. This usually happens about two months after the flowers have faded, typically in late summer or early fall, depending on your climate.

When the pods begin to split, it’s time to harvest. Snip the pods off with clean scissors or garden shears and place them in a paper bag to complete the drying process. Keep the bag in a warm, dry location with good air circulation to prevent mold from developing on the pods.

Don’t harvest seed pods that are still green or that show signs of disease or insect damage. These seeds are unlikely to be viable and could introduce problems into your growing area. Focus on collecting from your healthiest plants with the most desirable characteristics.

If you’re growing specific iris varieties, make sure to label each seed pod with the parent plant’s name and the date of collection. For those experimenting with cross-pollination, record both the pod parent (the plant that produced the seed) and the pollen parent (the plant that provided the pollen) to track your breeding efforts.

Step 2: Remove Seeds

Once the seed pods have fully dried, it’s time to extract the seeds. Carefully open the pods over a clean sheet of paper to catch any seeds that might fall out. Iris seeds are typically round or oval and range in color from light tan to dark brown, depending on the variety.

Inside the pod, you’ll find the seeds arranged in neat rows. Gently shake them out onto your paper, being careful not to damage them. If some seeds are stuck to the pod, you can use your fingers or a small tool like a toothpick to dislodge them.

After removing the seeds, take a moment to sort through them. Discard any that are very small, malformed, or showing signs of mold or insect damage. Quality is more important than quantity—you want to focus your time and resources on seeds that have the best chance of germination.

Once sorted, allow the seeds to air dry for another day or two to ensure they’re completely dry before storage or planting. If you’re not planning to sow them immediately, store them in paper envelopes labeled with the variety name and harvest date. Keep them in a cool, dry place until you’re ready to move to the next step.

Step 3: Soak

Before sowing, iris seeds benefit from a pre-treatment process to improve germination rates. Iris seeds have hard seed coats that can make it difficult for water to penetrate and for the embryo to emerge. A good soak helps soften this outer coating and jump-starts the germination process.

Place your iris seeds in a container with lukewarm water and let them soak for 24-48 hours. You might notice some seeds floating initially—this doesn’t necessarily mean they’re not viable, as the air trapped in the seed coat can cause buoyancy. Check back after a few hours; seeds that have absorbed water will typically sink to the bottom.

After soaking, most iris seeds require a period of cold stratification to break dormancy. Wrap the damp seeds in a moist paper towel, place them in a labeled plastic bag, and store them in your refrigerator (not the freezer) for 6-14 weeks, depending on the variety. Check the paper towel periodically to ensure it stays moist but not soaking wet.

Step 4: Sow in Trays

After the cold stratification period, your iris seeds are ready for sowing. Fill your seed trays or small pots with your seed starting mix, moistening it thoroughly before planting. The soil should be damp but not waterlogged—squeeze a handful and it should hold together without dripping water.

Plant your iris seeds about a half-inch deep in the soil. You can space them about an inch apart in trays, or plant 2-3 seeds per small pot. Cover the seeds with soil and gently firm it down with your fingertips to ensure good seed-to-soil contact. Don’t compact the soil too much, as this can make it difficult for seedlings to emerge.

Label each tray or pot with the variety name and sowing date. This is especially important if you’re growing multiple varieties, as iris seedlings can look very similar in their early stages of growth. Good record-keeping will help you identify your plants later and track which growing conditions produce the best results.

Cover your seed trays with clear plastic domes or wrap individual pots in clear plastic bags. This helps maintain consistent moisture and humidity levels that encourage germination. Place the trays in a warm location with bright, indirect light—a temperature between 65-75°F (18-24°C) is ideal for most iris varieties.

Step 5: Wait for Germination

Now comes the challenging part—waiting for your iris seeds to germinate. Depending on the variety, germination can take anywhere from a few weeks to several months. Be patient and resist the urge to disturb the seeds to check their progress.

During this waiting period, keep the soil consistently moist. Use a spray bottle to water gently when needed, avoiding heavy watering that could dislodge the seeds. The plastic cover will help retain moisture, but check regularly to ensure the soil doesn’t dry out completely.

As soon as you see the first green shoots emerging, it’s time to remove the plastic covering. Do this gradually—open the dome vents or poke holes in the plastic bags for a few days before removing them completely. This helps the seedlings adjust to the lower humidity levels they’ll experience as they grow.

Once the seedlings have their first true leaves (which follow the initial seed leaves or cotyledons), start feeding them with a diluted liquid fertilizer every two weeks. Use a fertilizer formulated for seedlings at half the recommended strength to avoid burning the delicate young plants.

Continue growing your iris seedlings indoors until they’re large enough to handle and all danger of frost has passed. This generally takes several months, so don’t rush this stage. When the seedlings have at least 4-5 leaves and are about 3-4 inches tall, they’re ready to be hardened off and transplanted to their permanent location in the garden.

Remember that your irises grown from seed may not bloom for 2-5 years, depending on the variety. This long wait is part of the adventure! Plant them in a special section of your garden where you can monitor their progress and enjoy watching them develop before they produce their first flowers.