How To Grow Bigger Blackberries

To grow bigger blackberries, you need to focus on three main things: proper pruning, consistent feeding, and smart watering.
 
If you’ve been wondering how to grow bigger blackberries, the answer isn’t just about planting them and walking away.
 
It’s about giving your plants exactly what they need at the right time, so they can pour all their energy into producing plump, juicy fruit.
 
In this post, we’ll walk through the exact steps you can take to grow bigger blackberries, from the soil they sit in to the way you train their canes.
 
Let’s get growing.
 

How to Grow Bigger Blackberries by Starting with the Soil

To grow bigger blackberries, you have to start underground.
 
Blackberries are heavy feeders, and they love soil that drains well but still holds moisture.
 
If your soil is compacted or sandy, your plants will struggle, and the berries will stay small.
 
Here’s how to fix that.
 

1. Test Your Soil pH First

Blackberries grow bigger blackberries when the soil pH sits between 5.5 and 6.5.
 
You can grab a cheap soil test kit online, and it takes ten minutes to get a reading.
 
If the pH is too low, add agricultural lime, and if it’s too high, mix in some elemental sulfur.
 
Getting this right means your plants can actually absorb the nutrients you give them.
 

2. Amend with Organic Matter

Compost is your best friend when you want to grow bigger blackberries.
 
Work two to three inches of aged compost into the top six inches of soil before planting.
 
This improves drainage, feeds beneficial microbes, and helps the soil hold water during dry spells.
 

3. Keep the Roots Mulched

A two-inch layer of straw or wood chips keeps moisture steady and suppresses weeds.
 
Weeds steal the water and nutrients your blackberry canes need to grow bigger blackberries.
 
Just don’t pile mulch against the canes themselves, as that invites rot.
 

how to grow bigger blackberries with Proper Pruning

Pruning is the single most powerful trick when you want to grow bigger blackberries.
 
Left alone, blackberry canes turn into a tangled mess that produces small, seedy fruit.
 
Here’s how to prune for size.
 

1. Remove Old Canes After Fruiting

Blackberries only produce fruit on second-year canes, called floricanes.
 
Once those canes finish fruiting, they’ll never produce again, and they just hog resources.
 
Cut them to the ground right after harvest so the plant pushes energy into the new canes.
 
That single habit is one of the biggest reasons some growers harvest bigger blackberries every year.
 

2. Thin the New Canes to Six or Eight per Plant

Healthy blackberry plants send up way more primocanes than they can support.
 
If you let them all grow, the plant spreads its energy thin, and every berry suffers.
 
Pick the six to eight strongest canes per plant and remove the rest.
 
Snipping the side branches back to twelve to eighteen inches also helps the plant grow bigger blackberries because more sap goes into fewer, stronger fruiting sites.
 

3. Tip the Primocanes in Summer

When new canes reach about four feet tall, pinch or cut off the top few inches.
 
This forces the cane to branch out, and each branch becomes a fruiting site next year.
 
The result is more berries per cane, and the berries themselves grow bigger.
 

4. Train Canes onto a Trellis

Blackberries that sprawl on the ground get poor airflow and uneven sunlight, which means smaller fruit.
 
A simple T-trellis with two wires keeps canes upright and lets light reach every leaf.
 
Good airflow also cuts down on disease, which is another sneaky reason berries stay small.
 

Feeding and Watering to Grow Bigger Blackberries

Even with great soil and perfect pruning, you still need to feed and water your plants correctly to grow bigger blackberries.
 
Here’s what that looks like in practice.
 

1. Fertilize in Early Spring

Blackberries wake up hungry in spring.
 
Apply a balanced fertilizer, like 10-10-10, at about one pound per plant when new growth starts.
 
Avoid too much nitrogen, though, because you’ll get giant leafy canes and tiny berries.
 

2. Side-Dress with Compost Mid-Season

Once the plants start flowering, give them a light side-dressing of compost or a low-nitrogen organic fertilizer.
 
This supports fruit development without pushing more leaves.
 
Remember, to grow bigger blackberries you need to feed the fruit, not just the foliage.
 

3. Water Deeply Once a Week

Blackberries need about one to two inches of water per week, especially from bloom to harvest.
 
Drip irrigation is ideal because it keeps the foliage dry and puts water right at the roots.
 
Shallow, frequent watering leads to weak roots and small berries, so water deep and let the top inch dry out between sessions.
 

4. Watch for Pests and Disease

Spotted wing drosophila and orange rust can wreck your crop and shrink the berries that do survive.
 
Check your plants weekly and remove any diseased canes immediately.
 
Healthy plants put their energy into growing bigger blackberries instead of fighting off problems.
 

So, How to Grow Bigger Blackberries

To grow bigger blackberries, start with soil that drains well and sits at the right pH, mulch the roots, and prune hard every year.
 
Then feed your plants in spring, water deeply each week, and keep pests away.
 
Do those things consistently, and you’ll grow bigger blackberries than you ever thought possible.