How To Plant Dahlias Sarah Raven – Her Expert Secrets For A Summer

ByRimon Chowdhury Updated on

Have you ever found yourself lost in the pages of a Sarah Raven catalogue, dreaming of those impossibly lush, vibrant dahlia borders? It’s a common gardener’s daydream. You see those perfect, dinner-plate-sized blooms and think, “Could my garden ever look like that?”

I’m here to tell you that yes, it absolutely can. The secret isn’t some unobtainable magic; it’s a reliable, time-tested method. I promise this guide will demystify the process and give you the confidence to grow dahlias that are the envy of the neighbourhood.

In this complete how to plant dahlias sarah raven guide, we’ll walk you through everything, step-by-step. We’ll cover choosing the best tubers, the crucial ‘waking up’ process, planting them out for maximum impact, and the essential care tips that ensure a non-stop parade of flowers from summer right through to the first frost. Let’s get our hands dirty and create that garden you’ve been dreaming of!

Why Trust the Sarah Raven Method for Dahlias?

Before we dig in, let’s talk about why this particular approach is so revered. Sarah Raven isn’t just a gardening personality; she’s a master of creating productive, beautiful, and long-lasting floral displays. Her method is built on a simple principle: give the plants a strong, early start to maximize their flowering potential.

The core of her technique involves potting up tubers indoors in early spring. This “waking up” process gives them a head start, protecting them from late frosts and pesky slugs while they are most vulnerable. By the time you plant them out in late May or early June, you have robust, leafy plants ready to explode with growth.

Following these how to plant dahlias sarah raven best practices means you’re not just planting a dormant tuber and hoping for the best. You’re nurturing a young plant, setting it up for a season of spectacular success. It’s one of the greatest benefits of how to plant dahlias sarah raven style—more flowers, for longer!

Getting Started: Your Dahlia Tuber Toolkit

A little preparation goes a long way in the garden. Before you even think about soil, gather your tools. Having everything on hand makes the process smooth and enjoyable. Think of it as your dahlia-planting mise en place!

Here’s what you’ll need for the initial potting-up stage:

  • Dahlia Tubers: Choose firm, healthy-looking tubers. They should feel solid, like a potato, not mushy or dried out. Look for a visible “eye” or a piece of the old stem, as this is where new growth will emerge.
  • Pots: A 2-3 litre pot is perfect for a single tuber. It gives the roots enough room to develop without being swamped in compost.

    • –

  • Potting Compost: A good quality, peat-free multi-purpose compost is ideal.
  • Labels: Trust me on this one. You will forget which variety is which. Label them clearly the moment you pot them up!
  • Watering Can: With a fine rose for gentle watering.

The Crucial First Step: Waking Up Your Tubers Indoors

This is where the magic begins! Potting up your dahlias indoors around late March or April (depending on your climate) is the single best thing you can do for a flower-filled summer. It gives them a 4-8 week head start in a safe, controlled environment.

Step 1: Prepare Your Pots

Fill your 2-3 litre pots about two-thirds full with your multi-purpose compost. Don’t press it down too firmly; you want it to remain light and airy to encourage root growth. A little tap on the bench is all you need to settle it.

Step 2: Position the Tuber

Gently place the dahlia tuber on top of the compost. It should look a bit like a strange bunch of sausages! The key is to identify the central stem from last year’s growth. Position the tuber so this stem is pointing upwards, as this is where the new shoots (or “eyes”) will appear.

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Don’t worry if you can’t see any shoots yet. Just get the orientation right. The knobbly crown should be facing up, and the dangly “sausage” bits down.

Step 3: Cover and Water Lightly

Cover the tuber with more compost until it’s just below the surface. The very tip of the old stem can be left peeking out. Water it in lightly—just enough to make the compost damp, not waterlogged. Overwatering at this stage is a common mistake and can cause the tuber to rot.

Step 4: Find a Bright, Frost-Free Spot

Place your potted tubers in a bright, warm, and frost-free location. A greenhouse, a conservatory, or even a sunny windowsill is perfect. Now, be patient! It can take a few weeks for the first green shoots to appear.

The Complete How to Plant Dahlias Sarah Raven Guide: From Soil to Sprout

Once the risk of all frost has passed (usually late May or early June in the UK), and your potted-up dahlias have produced strong, leafy growth of about 20-30cm, it’s time for the main event. This is the official how to how to plant dahlias sarah raven masterclass for getting them into the ground.

Step 1: Harden Off Your Plants

Don’t move your plants directly from their cozy indoor spot to the garden. This can shock them. For about a week, “harden them off” by placing them outside during the day and bringing them back in at night. This acclimatizes them to outdoor conditions.

Step 2: Prepare the Perfect Planting Spot

Dahlias are sun-worshippers. Choose a spot that gets at least 6-8 hours of direct sunlight a day. They are also hungry plants, so enrich the soil generously. Dig in plenty of well-rotted organic matter, like garden compost or manure. This improves drainage and provides vital nutrients.

Step 3: Dig the Right-Sized Hole

Dig a hole that is roughly the same depth as the pot and a little wider. You want the top of the root ball to sit level with the soil surface. Spacing is also key; give them plenty of room to grow. Aim for about 60-75cm (2-2.5 feet) between each plant for most varieties.

Step 4: Plant and Stake Simultaneously

This is one of the most important how to plant dahlias sarah raven tips. Place a sturdy stake or cane into the planting hole before you place the plant. Pushing a stake in later risks spearing the precious tuber. A 1.5m (5ft) stake is a good height for most dinner-plate varieties.

Gently ease the dahlia plant out of its pot, place it in the hole right next to the stake, and backfill with soil. Firm it in gently with your hands and tie the main stem loosely to the stake with soft garden twine.

Step 5: Water In Well

Give your newly planted dahlia a really good soak. This helps settle the soil around the roots and reduces transplant shock. A full watering can per plant is a good rule of thumb.

Essential Dahlia Care for a Season of Blooms

Planting is just the beginning! A little ongoing care will reward you with an astonishing number of flowers. This is your essential how to plant dahlias sarah raven care guide for the rest of the season.

Watering and Feeding

Dahlias are thirsty plants, especially once they start flowering. Water them deeply once or twice a week during dry spells. To promote an abundance of flowers, start feeding them with a high-potash liquid feed (like a tomato fertilizer) every two weeks from early July onwards.

The ‘Chelsea Chop’: Pinching Out for More Flowers

When your plant is about 30cm (12 inches) tall and has several pairs of leaves, it’s time to be brave! Pinch out the main growing tip, just above a set of leaves. This feels counterintuitive, but it encourages the plant to produce side shoots, resulting in a bushier plant and, ultimately, many more flowers. It’s a game-changer.

Deadheading Diligently

To keep the flowers coming, you must deadhead regularly. Once a flower starts to fade, snip the stem all the way back to a leaf joint. This tells the plant to produce more flowers instead of putting its energy into making seeds. Even better, cut the flowers for your home—the more you cut, the more they flower!

Common Problems with How to Plant Dahlias Sarah Raven (And How to Solve Them)

Even with the best care, you might run into a couple of issues. Don’t panic! These are usually easy to solve.

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The number one enemy of young dahlias is slugs and snails. They adore the tender new shoots. When you first plant them out, use your preferred method of control. Wool pellets, copper tape around pots, or torchlight patrols on damp evenings are great eco-friendly how to plant dahlias sarah raven solutions.

Another common issue is powdery mildew, a white dusty coating on the leaves, especially later in the season. Ensure good air circulation by not overcrowding your plants and by watering the base of the plant, not the leaves. Remove any affected leaves promptly.

Sustainable Dahlia Growing: Lifting and Storing Your Tubers

In most of the UK, dahlia tubers will not survive a cold, wet winter in the ground. Practicing sustainable how to plant dahlias sarah raven methods means saving your tubers to grow again next year. It’s cost-effective and rewarding!

After the first hard frost has blackened the foliage, cut the stems down to about 15cm (6 inches). Carefully dig up the tubers with a garden fork, being careful not to damage them. Gently brush off the excess soil and let them dry for a few days in a cool, airy place.

Once dry, store them in a cardboard box or crate filled with dry sand, sawdust, or shredded paper. Keep them in a cool, dark, and frost-free place like a garage or shed. Then, next spring, you can wake them up and start the whole wonderful process all over again!

Frequently Asked Questions About How to Plant Dahlias Sarah Raven

Can I plant dahlia tubers directly into the ground?

You can, but it’s riskier. Planting directly outside after the last frost means a much later flowering season. More importantly, the tender new shoots are extremely vulnerable to slugs. Potting them up first, as Sarah Raven recommends, gives you stronger plants and a much better success rate.

Why are my dahlias all leaves and no flowers?

This is usually caused by too much nitrogen in the soil or fertilizer. Nitrogen promotes leafy growth at the expense of flowers. Switch to a high-potash (high ‘K’ value) feed, like a liquid tomato food, to encourage bud formation. Also, ensure your plants are getting at least 6 hours of direct sun.

What does a dahlia ‘eye’ look like?

A dahlia ‘eye’ is a small, often reddish or purplish nub on the crown of the tuber, near the old stem. It looks a bit like the eye of a potato. This is the dormant bud from which the new shoot will grow. Sometimes they are hard to see until the tuber starts to warm up.

How often should I tie in my dahlias?

As the plant grows, you’ll need to add more ties to the stake. Check on them every couple of weeks. Add a new loop of soft twine for every 30cm (1ft) of new growth to keep the stems secure, especially before they get heavy with flowers or face strong winds.

Your Dahlia Adventure Awaits!

There you have it—the complete guide to planting dahlias the Sarah Raven way. It’s a method built on care, preparation, and a deep understanding of what makes these incredible plants thrive.

By giving your tubers a head start indoors, providing rich soil, staking them early, and caring for them throughout the season, you are setting the stage for a truly breathtaking display. The effort you put in during the spring will be returned a hundredfold in buckets of beautiful blooms.

So go on, choose those varieties you’ve been dreaming of, get your pots ready, and prepare for a summer filled with colour. Happy gardening!

Rimon Chowdhury
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