Zinnias are colorful, tough and don’t need that much in the way or care to get them to do well. And if you want some easy and bright flowers to add to your garden, balcony or even kitchen windowsill then zinnias are the perfect choice.
So growing them in pots is a no brainier!
So this guide will take you through everything you need to know to grow them successfully in pots. There’s tips to pick the right varieties, how and when to water, the light they need and more.
Why Grow Zinnias in Pots?
Zinnias flower easily and profusely, even when there isn’t much space. It’s one of the biggest reasons people love to grow them.
And in pots they can be moved around without any issues so you can find the best light conditions for them, protect them from pests and bring them indoors if the weather gets nasty.
Some of the main reasons to grow zinnias in pots:
- Easy to grow and maintain
- Aren’t affected by common pests
- Flowers all summer long if you deadhead them regularly
- Come in lots of sizes and colors
Zinnias are also fast growers, which means you won’t be waiting around forever to enjoy the hard work you’ve put in. In just a few weeks you can see beautiful flowers popping up.
Choosing the Right Zinnia Varieties for Pots
Some zinnias grow tall and others will stay small. So there ware some that are better suited for growing in pots.
Short and Compact Varieties
For smaller pots or containers you’re going to put on your balcony then a small or compact zinnia variety will be the better choice. Look for ones labeled as “dwarf” or “miniature.”
- Thumbelina Zinnia: These stay small, usually about 6 inches tall, but have wonderfully colorful flowers.
- Lilliput Zinnia: These are slightly taller and grow to around 18 inches and has double blooms.
Taller Varieties for Larger Pots
If you want to plant them in bigger pots then taller zinnias might be better. They look great on patios and make a real statement.
- State Fair Zinnia: Can grow up to 3 feet tall and have large flowers. They fill up a bigger space with their color.
- Zinderella Zinnia: Have unique looking and shaped flowers and grow to about 2 feet tall.
Getting Your Pots and Soil Ready
It’s a good idea to prepare your soil and pots first even though zinnias are generally laid back and don’t mind too much what they’re planted in.
Choosing the Right Pot
Zinnias roots are fairly shallow but they do need some room to spread out. So choose a pot that’s at least 12 inches in diameter and 10 inches deep to get the best results. If you’re planting more than one zinnia in the same pot then definitely go for a larger one.
Important pot tips:
- The pot must have drainage holes. Zinnias hate their roots getting too wet.
- Don’t use dark colored pots if you live somewhere hot as they will heat up quickly and dry out the soil.
- Terracotta pots are great for zinnias as they allow some air to get to the roots. But if you use one then be prepared to water them more often as they dry out faster.
Soil Preparation
Zinnias are pretty relaxed about the soil but if you want them to grow well use a high quality potting mix. Ideally look for a mix that’s:
- Drains well (zinnias don’t like sitting in water)
- Sandy or loamy
- Slightly acidic to neutral (so a pH 5.5 to 7.5)
You can mix in some compost or slow release fertilizer before you plant them. It can give a bit of a boost.
They don’t need particularly rich soil but giving them a little bit of nutrition at the start can help them grow strongly and even have more flowers.
Planting Zinnia Seeds or Seedlings
Now you’ve got the pot and soil ready so it’s time to plant the zinnias. You can do so either from seeds or use seedlings you’ve bought from a garden center.
Starting from Seeds
Growing from seed is really easy. They germinate quickly too. To do it:
- Sow the seeds about a quarter of an inch deep in the soil.
- Space them at least 6 inches apart. If you’re growing them in a small pot then plant only a couple of seeds maximum so they don’t get overcrowded.
- The soil should stay moist but don’t let it get waterlogged until the seeds germinate. They will usually start sprouting within about 5 to 7 days.
- Once your seedlings have a few sets of proper leaves you should thin them out if they’re too close together.
Planting Seedlings
If you’ve gone with seedlings then transplant them carefully to the pot. Dig a hole that’s a little larger than the root ball and put the seedling in. Cover with soil and water straight after you’ve planted them as it will help them to settle.
Caring for Zinnias in Pots
Now you’ve planted your zinnias you need to be looking after them properly. You should focus on:
Watering
They like to be moist consistently but not soggy. Keep the soil damp but don’t overdo it.
This the watering routine I follow:
- When the top inch of the soil feels dry then its time to water. When the weather is especially hot you may have to water every day.
- Don’t water from overhead as it can make the leaves wet and this leads to fungus problems. So water the soil directly.
- Try to water in the morning. This will give the zinnias a chance to dry off before the night and so mildew won’t develop.
Location and Light
Zinnias love the sun. If they get at least 6 to 8 hours of sun every day you’ll get the best flowers from them.
If your pot is on a balcony or patio make sure it’s getting full sun for most of the day. But if wherever they are outdoors doesn’t much sun the zinnias will still grow but just won’t flower as much.
Fertilizing Zinnias
Zinnias don’t need a lot of feeling but they appreciate a little boost with the right fertilizer as it will keep them healthy and giving you lots of flowers
Fertilizer Type
A balanced fertilizer works well for zinnias. Slow releasing is best. Something like a 10-10-10 or 14-14-14 mix would work perfectly. An organic fertilizer will work too if you want to stay natural.
How Often to Fertilize
- If you’re using a liquid fertilizer then use it once every 4 to 6 weeks throughout the growing season.
- Don’t go mad though. Too much fertilizer will result in too much nitrogen and that can make your zinnias grow more leaves and less flowers.
Deadheading and Pruning
Deadheading is important because it will help to keep your zinnias flowering all summer. You get rid of the spent flowers which allows the plant to direct its energy to producing more flowers instead of seeds.
How to Deadhead Zinnias
When you notice a flower fading then snip it off just above where new healthy leaves are. You can see flower buds forming within a week
Deadheading once a week should keep your zinnias looking tidy and at the same time will encourage more flowering.
Pruning for Bushier Growth
If you want your zinnias to be fuller, especially the taller varieties, it’s a good idea to pinch back the growing tips when they’re young. This should get the plant to branch out and will then become bushier.
Common Problems with Zinnias in Pots
They are mostly easy to look after but zinnias in pots can face a few problem. These are the main things to look out for:
Powdery Mildew
A fungus that looks like white powder on the leaves. Stop it by:
- Don’t water the leaves. Water the base of the plant.
- Make sure the plants have good air flow around then and also that they aren’t overcrowded in their pots.
If you do spot mildew on your zinnias then remove the leaf or leaves it’s on and use a fungicide to treat it. You can also try a homemade solution of water and baking soda which can work too.
Aphids and Other Pests
Aphids, spider mites and other pests can sometimes attack zinnias. The best way to avoid a big outbreak is by checking the undersides of the leaves on a regular basis. If you find any then spray them off with water or use insecticidal soap.
Final Thoughts
Growing zinnias in pots is fairly straightforward and a great way to add some color to somewhere like a patio or balcony. The don’t need much to do well but if you can then give them that extra bit of care with the right watering, light and deadheading. Doing so will mean you get flowers that are blooming all season.