Want to add a big splash of color to your patio or porch? Learning how to plant flowers in large planters is a fantastic way to start. It’s easier than you might think, and the results are instantly rewarding. This guide breaks it all down into simple, managable steps perfect for beginners. You’ll learn everything from picking the right pot to keeping your blooms thriving all season.
How To Plant Flowers In Large Planters
Let’s get started with the basics. A large planter is typically over 16 inches in diameter or height. These containers make a bold statement, but they do have some special needs. Their size means they hold more soil, which is great for plant roots but also means they can get very heavy. Don’t worry, though—with the right setup, you’ll create a beautiful, healthy home for your flowers.
Gathering Your Supplies
Before you begin, collect all your materials. Having everything on hand makes the process smooth and enjoyable. Here’s what you’ll need:
- A Large Planter: Choose one with at least one drainage hole in the bottom. Materials like fiberglass, resin, or wood are lighter than concrete or ceramic.
- Potting Mix: Use a high-quality potting soil, not garden dirt. It drains better and is formulated for containers. You’ll need more bags than you think!
- Flowers: Pick healthy plants from your local garden center. For large pots, a mix of thrillers (tall), fillers (medium), and spillers (trailing) works wonderfully.
- Drainage Material: Something like broken pottery shards, pebbles, or a piece of landscape fabric to cover the hole.
- Fertilizer: A slow-release granular fertilizer or a liquid feed for later in the season.
- Basic Tools: A trowel, gardening gloves, and a watering can or hose.
Step 1: Choose the Right Location and Planter
First, think about where your planter will live. Most flowering plants need at least 6 hours of sunlight daily. Check the plant tags for “full sun,” “part shade,” etc., and match them to your spot. Then, select your container. Ensure it has drainage holes—this is non-negotiable to prevent root rot. If you love a pot without holes, you can drill them yourself or use it as a decorative outer sleeve.
Step 2: Prepare the Planter for Drainage
Good drainage is the secret to healthy roots. Cover the drainage hole(s) with a piece of broken pot or a stone. This stops soil from washing out while letting water escape. Some gardeners skip adding a layer of gravel at the bottom; modern thinking says it’s not necessary and can actually hinder drainage. The key is using that good potting mix.
Tip: Making Heavy Planters Movable
Large planters full of soil are immovable. Place your empty pot on a plant caddy with wheels before you fill it. This lets you rotate the planter for even sun exposure and move it if needed.
Step 3: Fill with Potting Mix
Now, fill your planter about one-third to halfway with potting soil. Do not pack it down tightly; you want it loose for roots to grow easily. At this stage, mix in a slow-release fertilizer according to the package directions. This gives your flowers a steady supply of nutrients for weeks.
Step 4: Arrange and Plant Your Flowers
This is the fun part! While your plants are still in their nursery pots, arrange them on top of the soil layer. Play with different layouts. A classic method is the “thriller, filler, spiller” technique.
- Thriller: One tall, eye-catching plant in the center or back (e.g., ornamental grass, salvia).
- Filler: Mid-size, bushy plants that surround the thriller (e.g., geraniums, begonias).
- Spiller: Vines that cascade over the edge (e.g., sweet potato vine, lobelia).
Once you’re happy with the layout, it’s time to plant. Gently remove each plant from its plastic pot by squeezing the sides and tipping it out. Loosen the roots slightly if they are tightly wound. Dig a small hole in the potting mix, place the plant in, and fill around it with more soil. Repeat for all plants, keeping the soil level about 1-2 inches below the planter’s rim to leave room for watering.
Step 5: Water Deeply and Mulch
After planting, give your new arrangement a thorough, deep watering. Water until you see it running out of the drainage hole. This settles the soil around the roots. To help conserve moisture and reduce weeds, add a thin layer of mulch like bark chips or cocoa hulls on top of the soil. This step is often overlooked but really helps in hot weather.
Caring for Your Potted Flowers
Your job isn’t over after planting. Consistent care keeps the display looking its best.
Watering Wisely
Large planters can dry out slower than small ones, but they also need more water volume when they do. Check soil moisture by sticking your finger an inch into the soil. If it’s dry, water deeply. In peak summer, this might mean watering daily. Early morning is the best time to water.
Feeding for Continuous Blooms
The slow-release fertilizer you added will last for months. For an extra boost, especially for heavy bloomers like petunias, use a liquid flower fertilizer every two weeks. Follow the label instructions carefully—more is not better.
Deadheading and Pruning
To encourage more flowers, regularly remove spent blooms. This is called deadheading. Simply pinch or snip off the old flower heads. Don’t be afraid to trim back leggy plants by a third to promote bushier growth.
Seasonal Considerations
Most annual flowers will last until the first frost. When that happens, you can empty the planter and store it for winter. If you used perennials, you can sometimes leave the whole container in a sheltered spot, or plant them in the ground before winter arrives.
Common Mistakes to Avoid
Even experienced gardeners make errors. Here’s how to sidestep common pitfalls:
- Using Garden Soil: It compacts in pots, suffocating roots. Always use potting mix.
- Overcrowding: It’s tempting to pack plants in for instant fullness, but they need space for air circulation and growth. Follow spacing guidelines on tags.
- Forgetting to Fertilize: Potting soil nutrients get used up quickly. Regular feeding is essential for blooms.
- Inconsistent Watering: Letting soil dry out completely then flooding it stresses plants. Try to maintain even moisture.
FAQ: Planting Flowers in Big Pots
What is the best soil for large flower planters?
A high-quality, general-purpose potting mix is perfect. Look for one with added perlite or vermiculite for good drainage.
How many flowers should I put in a large planter?
It depends on the mature size of the plants. For a 20-inch pot, 5-7 smaller plants often works well. Use the “thriller, filler, spiller” formula as a guide.
Do I need to put rocks in the bottom of a large planter?
It’s a common myth. You don’t need a rock layer. Just cover the drainage hole to prevent soil loss and use a good potting mix throughout.
How often do you water flowers in large containers?
There’s no fixed schedule. Check the soil daily in warm weather by feeling it with your finger. Water when the top inch is dry.
Can I mix vegetables and flowers in a large planter?
Absolutely! Many vegetables like lettuce or peppers look great with flowers like marigolds or nasturtiums. Just ensure they have similar light and water needs.
Starting your first large planter is an exciting project. By following these simple steps—choosing the right container, using proper soil, planting carefully, and providing consistent care—you’ll create a stunning focal point for your outdoor space. The best part is watching your flowers grow and change throughout the season, all thanks to your efforts. Grab a pot and some soil, and give it a try this weekend.