What Plants Grow Well In Cinder Blocks

If you’re short on garden space, you might be wondering what plants grow well in cinder blocks. This simple, low-cost method is perfect for creating a thriving garden in small spaces like patios, balconies, or narrow side yards. You can turn these humble concrete blocks into a productive and attractive vertical planter. It’s a fantastic way to grow herbs, vegetables, and flowers without needing a traditional garden bed.

Let’s look at how to get started and make the most of your cinder block garden. The process is straightforward and rewarding.

Not every plant is suited for the unique conditions of a cinder block hole. The space is confined and the concrete can absorb heat. You need plants that have compact root systems and can handle a bit of stress. The good news is, many excellent choices fit this description perfectly.

Best Herbs for Cinder Block Gardens

Herbs are arguably the top performers. They naturally thrive in well-drained conditions and don’t need deep soil. A sunny cinder block planter is ideal for them.

Thyme: This hardy, low-growing herb loves sunshine and excellent drainage.
Oregano: It spreads nicely and is very drought-tolerant once established.
Rosemary: Prefers drier soil, making the block’s drainage a benefit.
Chives: Their grassy clumps grow well in confined spaces and you can harvest them repeatedly.
Mint: Be careful—it’s vigorous. Growing it in a single block hole actually helps contain its spread.
Lavender: Needs full sun and hates wet roots, so the block’s drainage is perfect.

Top Vegetables to Try

Many vegetables will produce a great harvest from a cinder block. Focus on varieties that are bred for containers or small spaces.

Leaf Lettuce & Spinach: You can succession plant these for a continuous harvest. They have shallow roots.
Radishes: They grow so fast and don’t need much room at all.
Green Onions (Scallions): You can plant the root ends from store-bought ones and they’ll regrow.
Bush Beans: Choose “bush” types, not pole beans. A few plants can give you a steady supply.
Swiss Chard: It’s both beautiful and edible, tolerating some heat better than spinach.
Dwarf Peppers: Look for compact or “patio” varieties. They love the warmth the blocks retain.

Excellent Flower Choices

Flowers add color and attract pollinators to help your edible plants. These are tough bloomers that do well in tight spots.

Marigolds: A classic. They repel some pests and their bright colors last all season.
Nasturtiums: The leaves and flowers are edible with a peppery taste. They trail beautifully.
Alyssum: Forms a sweet-smelling, low carpet that spills over the blocks.
Pansies/Violas: They add cheerful color and are also edible.
Sedum (Stonecrop): Extremely drought-tolerant succulents that thrive on neglect.

How to Prepare Your Cinder Blocks for Planting

Proper setup is key to your plants success. You can’t just fill the holes with dirt from your yard. Follow these steps to create a healthy environment.

Step 1: Choosing and Placing Your Blocks

Always use standard concrete cinder blocks, which have two large holes. Avoid older blocks that might contain fly ash, though modern ones are generally safe. Place them on a stable, level surface that gets at least 6 hours of sunlight. You can arrange them in a single row, stack them for a tiered effect, or create a U-shape.

Step 2: Drainage is Non-Negotiable

Blocks have open bottoms, which is good, but you must ensure they aren’t sitting flat on a solid surface. If placing on concrete, use small stones or pot feet under the block’s edges to lift it slightly. This allows excess water to escape and prevents root rot.

Step 3: Filling with the Right Soil Mix

This is the most important step. Regular garden soil is too dense. You need a light, nutrient-rich mix.

Start with a handful of small rocks or gravel in the very bottom of each planting hole for extra drainage.
Fill the hole with a high-quality potting mix. Do not use soil from your yard.
Mix in a slow-release organic fertilizer or compost. The blocks have limited soil volume, so nutrients need to be packed in.
Water the soil thoroughly before planting to settle it and eliminate air pockets.

Planting and Ongoing Care Tips

Now for the fun part—putting your plants in! Care is a little different than for in-ground plants.

Planting Your Seedlings or Seeds

You can start with small nursery plants or sow seeds directly. For most herbs and vegetables, one plant per hole is plenty. For very small things like radishes or alyssum, you might fit 2-3. Gently loosen the roots of a seedling, make a hole in the soil of the block, place it in, and firm the soil around it. Water it in right away.

Watering Your Cinder Block Garden

The concrete wicks moisture and the soil volume is small, so your blocks will dry out faster than a regular garden. Check the soil daily by sticking your finger in an inch deep. If it feels dry, water slowly until it runs out the bottom. Early morning is the best time to water.

Feeding for Best Results

Because you water frequently, nutrients wash out of the soil faster. Supplement your initial fertilizer with a liquid feed every 2-3 weeks during the growing season. A balanced organic liquid fertilizer or compost tea works very well. Just follow the instructions on the label for container plants.

Creative Layout and Design Ideas

Cinder block gardens can be surprisingly attractive. Think beyond a simple line.

Vertical Pyramid: Stack blocks in a staggered pattern to create a pyramid. Plant trailing plants like nasturtiums in the top blocks.
Herb Spiral: Arrange blocks in a spiral pattern, planting different herbs in each section. It looks great and saves space.
Privacy Screen: Create a low wall by stacking blocks two high. Plant tall, narrow plants like lavender or chives in the top holes.
Color Coding: Paint the blocks before planting! Use outdoor paint in colors that complement your plants or house.

Common Problems and Simple Solutions

Even the best gardens face a few issues. Here’s how to handle common ones.

Soil Drying Too Fast: Mix water-retaining crystals into your potting soil or add a thicker layer of mulch on top of the soil in each hole.
Weeds: They are less common in fresh potting mix, but can appear. Just pull them by hand as soon as you see them.
Overwatering: Soggy soil is a killer. Always check soil moisture before watering. Ensure your blocks have good drainage underneath.
Nutrient Deficiency: If leaves turn yellow, it’s likely a nutrient issue. Apply a liquid fertilizer.

FAQ About Cinder Block Gardening

Are cinder blocks safe for growing vegetables?

Modern concrete cinder blocks are generally considered safe for gardening. If you are concerned about older blocks, you can line the planting holes with landscape fabric or use a food-safe sealant on the inside surfaces. This creates a barrier between the soil and the block.

Do I need to seal or paint the blocks?

You don’t need to, but painting with an outdoor latex paint can make them look nicer and may slightly reduce the porousness, keeping soil moist a bit longer. Always let paint cure fully before planting.

What’s the best soil mix for plants in blocks?

A high-quality, all-purpose potting mix is your best bet. Avoid cheap mixes that compact easily. You can make your own by mixing two parts potting mix with one part compost and one part coarse perlite or vermiculite for drainage.

Can I grow tomatoes in cinder blocks?

Most tomato plants get too large and have too big of a root system. However, some very compact “micro dwarf” or “patio” tomato varieties might succeed if you plant only one per block hole and are diligent with watering and feeding.

How do I winterize my cinder block garden?

In cold climates, the soil in the blocks will freeze. At the end of the season, remove annual plants and soil. You can store the blocks, or leave them empty. For perennial herbs like thyme, you can insulate the block by wrapping it in burlap, but success depends on your climate’s severity.

Starting a cinder block garden is a simple project with big rewards. With the right plant choices and a little daily attention, you can enjoy fresh herbs, vegetables, and flowers even in the smallest outdoor area. It’s a testament to how a little creativity can lead to a thriving garden. Give it a try this weekend—you might be surprised by how much you can grow.