When to Plant Ranunculus in Zone 6: A Detailed Guide

When to plant ranunculus in Zone 6? The best time for planting ranunculus is during late winter or early spring, around February 6-7. This time is around 12 weeks before your last spring frost, which averages from April 1-21.

Regions in Zone 6 are known for cold winters averaging -10° to 0°F, and frost can kill off these plants. Therefore, the survivability rate of ranunculus decreases when temperatures fall below 25°F.

Keep reading to discover how to successfully grow ranunculus and more tips.

Best Time to Plant Ranunculus in Zone 6

Unlike the hardiness zones from 8 to 10 with their mild winters that are the most ideal for ranunculus flowers, you have to adjust your planting calendar in zone 6 for late winter or early spring.

The rule of thumb is to plant your ranunculus corms indoors 12 weeks before your last spring frost.

For Zone 6, take note of the following:

1. Average Last Spring Frost Date: April 1-21
2. Average First Fall Frost Date: October 17-31

Taking the above dates into consideration, the ideal time would start around the 6th and 7th of February. If you do that, you should be seeing ranunculus blooms by late spring or early summer.

However, it’s important to remember that the frost dates we’ve listed are only averages and are never constant.

How to Grow Ranunculus

Now that we know, when the best time for planting ranunculus is, let’s go into detail about how you actually cultivate them in this planting guide:

1. Soaking

Many gardeners like to debate whether this step is necessary. In fact, this step is optional and is preferred by those who want their pre-sprouted ranunculus seedlings to grow at least three weeks earlier.

However, if you choose to soak, you need to make sure you do it right by following these pointers:

1. When soaking your dormant corms, please keep track of the time and make sure it doesn’t go over the limit of 4 hours. Any longer, you risk your corms absorbing too much water, leading to rot.
2. Don’t let the water go over 55°F. To do this, switch out the water every hour.
3. If you prefer not to dump water constantly, you can use an aquarium pump or a steady but gentle stream of water flowing in for the entire soaking process.

2. Pre-Sprouting

Before you plant ranunculus bulbs in garden beds or containers, it’s best to pre-sprout them by doing these steps:

1. Fill a flat planting tray with a potting mix that’s slightly moist but not wet.
2. Place the soaked corms with their tubers pointing down. You don’t have to worry too much about spacing since they’ll only be there for two weeks at most.
3. Top them off with more potting mix of the same moisture level from before. Go for a coverage of less than an inch.
4. Look for an area that’s relatively cool and dry. Make sure it’s well away from any sunlight as well. Think of a basement or even just an empty room that’s cut off from the heating line with no windows or with closed curtains.
5. The temperature you’re going for is 50°F.
6. Pre-sprouting takes about two weeks. By then, you will see roots beginning to sprout which means you’re ready for the next step.

3. Planting Outside

1. Ranunculus thrives in well-draining soil under the full sun. The pH soil level should be ideally 6 to 7.
2. When planting the corms in beds, keep them apart with 5-8 inches in between and about 2 inches deep into the ground.
3. If you have no choice but to plant your ranunculus sprouts earlier than ideal, make sure they’re covered up with a frost cloth.
4. You should also learn to recognize the signs of frost damage. Common signs include wilt and black foliage or flowers. Cut off the damaged parts and see if their condition improves within a few days.

4. Planting Indoors

It is indeed possible, and arguably the best way, to plant and grow ranunculus in pots without the need for transplanting them outside.

1. Make sure to choose a pot that’s well-draining and preferably hoisted off the ground.
2. The minimum space in between corms should be 6 inches to not risk overcrowding.
3. For an 8 inch-pot, you can use one plant. In a 12-inch pot, two will do just fine. If you wanna go for three, you would need an 18-inch pot.
4. You don’t have to worry about planting too shallow as well since ranunculus varieties don’t come with an overly complicated root system.

Overall, the different ranunculus growth stages take 90 days to complete once planted. You can expect stems to grow up to 18 inches. For the blooms, they will last between 4 to 7 weeks.

5. After-Care

1. Once blooming ends, keep the foliage intact to soak up the sun for stronger bulbs in future ranunculus seasons.
2. You can start removing them when the leaves begin to yellow. This means the plant is going back to dormancy.

Read next: Best time to plant ranunculus in zone 7.

Tips for Successful Ranunculus Planting in Zone 6

1. If your soil isn’t well-drained enough, you can remedy this by adding 2-3 inches of organic fertilizer.
2. If your region doesn’t get enough sun in a day, it’d be better to plant ranunculus in potted containers since you can move them around to catch the sunlight.
3. When watering, it’s safe to water your ranunculus only when hot and dry weather continues for an extended period. Make sure the mature blooms are fully dry before dousing them again.
4. If you already amended your ranunculus with organic material to improve the soil’s draining ability, you can opt not to fertilize it. Otherwise, use a liquid fertilizer bimonthly.

Conclusion

The perfect time when to plant ranunculus in zone 6 starts on February 6-7 until the spring season arrives in March. In zone 6’s climate, you want to avoid cold winters and hot summers which are not healthy for ranunculus.

Even if these perennials are not really hardy in colder zones, you can still make it work. Just follow our list of essential tips and with enough determination and careful planning, you can get a whole assortment of ranunculus colors blooming soon.