If your zinnias aren’t quite what you imagined and looking dried and unhappy rather then bright and cheerful then you’re not alone. Zinnias are generally tough but like all flowers they’re not invincible.
And I know how frustrating it can be to plant a new flower and wait for it to give you some beautiful blooms but instead you have to watch to wither away and have no idea what went wrong.
So if you’ve been struggling to get your Zinnias to really thrive then this guide will look at reasons they’re struggling. Drooping, discolored and dying zinnias? There’s a reason and I’ll take you through what the causes could be and how to fix them.
1. Watering: Too Much or Too Little
When your zinnias are starting to look unhappy you should be looking at how you’re watering them first. Depending on how you are doing it water can either be the best thing for your flowers or the worst.
How Much Water Do Zinnias Need?
Zinnias like moderate watering on a consistent basis. You should be aiming for about 1 inch per week, especially when they’re young.
They really don’t like to sit in soggy soil! But you’ll need to be careful you don’t go the other way. Too little water will leave them dehydrated.
Signs of Overwatering
- Yellowing leaves – particularly when the leaves are turning yellow from the bottom of the plant moving up.
- Wilted or mushy stems – even when the soil seems wet.
- Fungus growing on the soil or the plant.
Signs of Underwatering
- Dry, crispy leaves – starting at the edges.
- Wilting in the heat of the day – and not perking up in the evening.
- Buds that aren’t opening or flowers that are fading too fast.
How to Water Correctly
Water early in the morning at the base of your zinnias as it will give the roots long enough to absorb the water before it gets hotter in the day.
If you live somewhere that gets very hot you may need to give them more water. Just be sure the soil has dried out completely before you water again.
2. Poor Soil Quality
Zinnias aren’t too fussy about soil but if it’s poor quality or you haven’t prepared it properly then they can suffer. The soil should drain well and have a decent balance of nutrients for them to do well in.
What Soil Type Do Zinnias Like?
Zinnias like soil with a pH level between 5.5 and 7.5. If the pH isn’t right then they can have issues with absorbing the nutrients properly. This can result in yellowing leaves and not growing fully.
Common Soil Problems:
- Compacted soil: when the soil becomes too compacted and the air and water can’t get through it this leads to the roots suffocating.
- Poor drainage: If the soil your zinnias are in holds on to the water it can also cause root rot.
- Lack of nutrients: Zinnias need some feeding to keep them flowering especially if they’re growing in pots.
Solution:
If your soil isn’t good quality or is compacted then you can try mixing in some compost to help with the drainage and nutrients. You can do a soil test first to check and see whether the pH levels need adjusting.
| Soil Issue | Symptoms | Solutions |
|---|---|---|
| Compacted soil | Slow growth, yellowing leaves | Add compost and get air through the soil |
| Poor drainage | Root rot, wilting and soggy soil | Improve the drainage of the soil and try using raised beds |
| Nutrient deficiency | Stunted growth, pale leaves | Add fertilizer or compost |
3. Location
Zinnias need a lot of sunshine to do best. If they get less than 6 hours a day then they could easily end up leggy and with weak stems and few flowers.
Best Sunlight for Zinnias:
Zinnias love full sun. That means they should be getting a minimum of 6 to 8 hours of direct sunlight every day.
If you’ve planted them somewhere shady then they’ll be stretching towards the sun and probably become leggy. This will make them weaker and more likely to pick up diseases and problems.
What Happens If Zinnias Don’t Get Enough Light?
- Leggy growth – the stems get too long and thin.
- Fewer flowers – they won’t bloom as often and their flowers will be smaller.
- Weaker plants – they will be more likely to be affected by pests and diseases because they’re not as strong as they could be.
If they’re not getting enough light then move them to a sunnier spot. Or at the very least trim any branches or plants that are causing them to have shade they otherwise wouldn’t.
4. Pests
Zinnias may be tough but that doesn’t stop the pests targeting them. It could be aphids, caterpillars, spider mites etc. as all of them will do damage to your zinnias.
Common Zinnia Pests:
- Aphids: Will cause the leaves to curl, become disrupted or turn yellow.
- Spider Mites: If your zinnias are looking dusty and a bit faded this could be because of spider mites. You can identify them by looking for tiny webs under the leaves.
- Caterpillars: They will eat the leaves and flowers of zinnias leaving behind holes.
How to Deal with Pests:
- Aphids: Try spraying the plants with a mixture of water and a tiny amount of dish soap. You can also use aphid predators like ladybugs to deal with them.
- Spider Mites: Increase the humidity around your plants (spider mites hate moisture) and use water on the undersides of the leaves.
- Caterpillars: Pick them off the plants with your hands if you can. Or use organic insecticide like Bt (Bacillus thuringiensis).
5. Disease
Fungal diseases are common on zinnias, even more so if they’re overcrowded or the humidity levels are high. Powdery mildew, in particular, is seen a lot. You can identify it as a white, powdery substance on the leaves.
Common Diseases:
- Powdery Mildew: It looks like the zinnias have been dusted with flour. It usually starts on the lower leaves and works its way up.
- Leaf Spot: Dark brown or black spots on the leaves which will spread if you don’t treat them.
- Root Rot: Caused by overwatering or poor drainage. It will result in yellowing leaves and if not dealt with the the zinnia will eventually collapse entirely.
How to Prevent Diseases:
- Spacing: Give your zinnias room to breathe. If they’re crowded then they’ll get more humid and fungus might develop.
- Watering: Water at the base to keep the leaves dry. Fungi will grow and spread on foliage that is wet.
- Air circulation: Prune them on a regular basis so the air flow is good. This is more important if they’re growing in humid areas.
6. Temperature Stress
As I’ve already mentioned – Zinnias are pretty resilient. But extreme temperatures are one area that they will struggle with.
Extreme heat or cold can cause major stress and will almost certainly cause them to become less healthy.
How Hot is Too Hot for Zinnias?
While they love the warmer weather they will start to struggle if temperatures get above 90°F for long periods of time. They will wilt at the hottest parts of the day but if you see them recovering in the evening then they’re probably stressed and not dying.
How Cold is Too Cold?
As zinnias are annuals it means they don’t like frost. Anything below 50°F can cause them to slow down and a frost will kill them completely.
If you get a cold snap you weren’t expecting then you might need to cover them overnight with a light sheet or move any growing in pots inside.
7. Neglecting Deadheading
Deadheading is important for zinnias. They need some maintenance to stay at their best and deadheading is one of the most important ways to make sure they stay flowering throughout the season.
Why Deadhead Zinnias?
Zinnias went to set seed and once they’ve started to produce seeds they’ll stop flowering. So when you remove any spent flowers you’re actually tricking your zinnia into focusing on flowering rather than producing seeds.
How to Deadhead:
- Look for flowers that are starting to fade.
- Use a pair of scissors or shears and snip the stem just above a leaf node or set of healthy leaves.
- Do this often to keep the flowers coming!
8. Poor Fertilization
Fertilizing isn’t something zinnias are desperate for but it does help. If you’re not fertilizing your zinnias at all or if you’re overdoing it you could end up with problems.
What Kind of Fertilizer Do Zinnias Need?
A balanced fertilizer, like a 10-10-10 or 20-20-20 blend, works well for zinnias. If they get too much nitrogen though then they can begin to give you fewer flowers and instead more leaves.
When to Fertilize:
- Before planting: Mix compost or fertilizer into the soil.
- Mid-season: If your plants are looking a bit tired then giving to them a little bit of ferilizer can work as a boost.
Signs of Over-fertilization:
- Too many leaves growing and noticeably fewer flowers.
- Burnt leaf tips or edges.
- Weak and leggy growth.
Final Thoughts
Zinnias are wonderful to grow and relatively straightforward. But as with most plants and flowers they have eccentricities.
Once you understand the problems we’ve gone through here you should be well placed to save your flowers from an early death. Treat them right and you won’t have any problems and instead can enjoy their beautiful flowers from summer to frost.
