Container Gardening
Grow corn in Rubbermaid tubs on balcony 90 day ears
Learn how to grow corn Rubbermaid tubs balcony in your apartment. Step-by-step guide with photos, calculator links, and supply list.
Why This Method Works
When I first started urban gardening years ago, the idea of growing corn, that quintessential symbol of open fields, on my tiny apartment balcony seemed utterly ridiculous. But I'm here to tell you it's not just possible; it's genuinely rewarding. The secret lies in a combination of smart container choice and understanding corn's specific needs. Growing corn in Rubbermaid tubs on a balcony leverages several key principles that make it surprisingly effective for apartment dwellers. First, size matters. Most backyard gardeners plant corn in rows, but for containers, the focus is on creating a dense block for pollination. Corn is wind-pollinated, and individual plants are both male (tassel) and female (ear silks). For successful kernel development, pollen needs to drift from the tassel onto the silks of nearby plants. A group of plants in a large container, even if tightly spaced, mimics a mini-field, increasing the chances of good pollination. Second, control. In a container, you have absolute control over the soil medium, nutrients, and moisture. This is a massive advantage over in-ground planting, especially if your native soil is poor. I’ve found that I can tailor the environment precisely to what corn thrives on, leading to robust growth and sweet kernels. Finally, the Rubbermaid tub itself. These aren't fancy terracotta pots; they're readily available, inexpensive, durable, and, critically, they're deep and wide enough to support corn's extensive root system and house a decent cluster of plants. Their dark color can help warm the soil, too, which corn appreciates.What You'll Need
Getting started with balcony corn isn't complicated, but having the right supplies makes all the difference. Here’s a breakdown of what I recommend:Container: Rubbermaid Tub
I specifically look for Rubbermaid ActionPacker Totes or similar heavy-duty storage tubs. The 35-gallon or 50-gallon sizes are ideal. A 35-gallon tub (around 20"W x 31"L x 17"H) can comfortably hold 4-6 corn plants, while a 50-gallon tub (around 20"W x 38"L x 17"H) can fit 6-8. Always ensure they are *food-grade* if you're concerned about plastics leaching, though for annuals like corn, I personally don't find it to be a significant issue with standard heavy-duty tubs. The key is depth – corn roots go deep!Growing system: Container Gardening
This isn't a hydroponic setup; it's straight-up soil-based container gardening. The principles are familiar to anyone who's grown tomatoes in a pot, just scaled up for a larger, thirstier plant.Other materials
- Drill with a 1/2-inch bit: Essential for drainage holes. Don't skip this, or your corn will drown. I usually drill 8-10 holes evenly spaced on the bottom of each tub.
- Potting mix: This isn't the place for cheap garden soil. You need a high-quality, well-draining potting mix. Look for bags specifically labeled for containers that contain perlite or vermiculite. You'll need a lot – a 35-gallon tub will require at least 3-4 bags of 1.5-2 cu ft potting mix. For precise measurements, especially with soil volume, I found it incredibly helpful to **check out our soil volume calculator** to estimate exactly how much soil you'll need based on your tub's dimensions.
- Compost or aged manure: About 10-20% of your total soil volume should be good quality compost or aged manure. Corn is a heavy feeder.
- Slow-release granular fertilizer: A balanced fertilizer (e.g., 10-10-10 or 14-14-14) is a good start. I mix this in when I prepare the soil.
- Liquid organic fertilizer: Fish emulsion, compost tea, or a balanced liquid feed (like 5-1-1 or 2-4-2) for supplemental feeding later in the season.
- Corn seeds: Look for "short-season" or "early maturing" varieties specified for 60-75 days to maturity. "Mirai Hybrid" or "Honey & Pearl" are excellent choices. I’ve had success with both. Avoid "field corn" varieties as they grow too tall and take too long.
- Watering can or hose with a gentle shower setting: Consistent moisture is critical.
- Optional: Stakes or support cages: Some varieties can get top-heavy and appreciate extra support, especially on a windy balcony. Tomato cages or bamboo stakes work Well.
Step-by-Step Guide
This 90-day timeline is a general guideline; always adjust based on your specific climate and corn variety.Days 1-3: Setup
- Drill drainage holes: Flip your Rubbermaid tubs upside down and drill 8-10 1/2-inch holes in the bottom for drainage. Without good drainage, your corn roots will rot.
- Prepare the soil: In a large mixing area (or right in the tubs), thoroughly combine your potting mix with compost/aged manure and your slow-release granular fertilizer. Mix it well – you want a uniform, nutrient-rich base.
- Fill the tubs: Fill your tubs to within 2-3 inches of the rim.
- Planting the seeds: Corn likes to be planted in a block for good pollination. For a 35-gallon tub, I usually plant 6 seeds in a hexagonal pattern, about 6-8 inches apart. For a 50-gallon tub, I'd go for 8 seeds. Plant them about 1 inch deep. **If you're unsure about precise plant spacing for optimal pollination, our plant spacing calculator can help you visualize the best arrangement for your container size.**
- Water gently: After planting, water thoroughly until you see water draining from the bottom holes. This settles the soil and initiates germination.
Days 4-7: Initial Growth
You probably won't see much action in the first few days, but inside the seeds, things are stirring. Keep the soil consistently moist but not waterlogged. Warm temperatures (above 60°F / 15°C) are crucial for germination. If it's too cool, consider covering the tubs with clear plastic for a few days to create a mini-greenhouse effect.Days 8-14: Emergence and Thinning
- Sprouts! You should see your corn seedlings emerge, often within a week if conditions are right.
- Thinning: Once the seedlings are 3-4 inches tall and have their first true leaves, it's time to thin. I thin down to 4-5 vigorous plants per 35-gallon tub and 6-7 per 50-gallon tub. Cut the weaker seedlings at the soil line with scissors to avoid disturbing the roots of the keepers.
Days 15-30: Vegetative Growth (Early Stage)
- Consistent watering: Corn is a thirsty plant, especially in containers. Check the soil daily. If the top inch feels dry, water deeply.
- First liquid feed: Around week 3-4, when plants are about a foot tall, I give them their first dose of liquid organic fertilizer. Follow package directions, but I usually dilute it a bit more than recommended for weekly feeding.
- Pest check: Keep an eye out for common pests like aphids. A strong blast of water or insecticidal soap can usually handle early infestations.
Days 31-60: Rapid Growth & Tassel Formation
This is when your corn really takes off.- Increased watering: As plants grow, their water needs skyrocket. You might need to water twice a day during hot, sunny weather. Wilting leaves are a sign of thirst.
- Fertilizing: Continue with weekly or bi-weekly liquid feeds. Focus on a balanced fertilizer or one slightly higher in nitrogen to support leafy growth.
- Tassels appear: Around days 45-60, you'll see the male flowers (tassels) emerge from the top of the plant. These produce pollen.
- Silks develop: Soon after, the female flowers (silks) will emerge from the leaf axils lower down the stalk. Each silk is connected to a potential kernel.
- Pollination encouragement: Once silks appear, gently tap the tassels a few times a day to encourage pollen to drift onto the silks. This is crucial for full ears. On windy days, nature does most of the work, but a little assist from you helps ensure every kernel is pollinated.
- Support (if needed): If your plants are getting very tall and your balcony is windy, now is a good time to stake them.
Days 61-90: Ear Development & Harvest
The final stretch!- Continuous watering & feeding: Maintain consistent watering and feeding. This is when the ears are filling out, and they need plenty of nutrients and moisture.
- Monitoring for maturity: Corn is ready to harvest when the silks turn brown and dry, and when you can feel plump kernels if you gently peek under the husk. A traditional test is to puncture a kernel in the middle of the ear with your thumbnail – if a milky liquid squirts out, it's ready. If it's watery, it's too early; if it's pasty, it's too late.
- Harvesting: Grab the ear firmly and twist it downwards and away from the stalk. It should snap off cleanly. Don't leave ripe ears on the plant; they'll quickly pass their prime.
Common Mistakes to Avoid
I've learned these the hard way, so you don't have to!- Insufficient drainage: This is probably the number one killer of container plants. If you don't have enough drainage holes, roots sit in water, leading to rot and fungal issues. Always drill more holes than you think you need!
- Not enough plants (poor pollination): Planting just one or two corn stalks in a container virtually guarantees very few, if any, kernels. Corn needs to be planted in a block for successful wind pollination. Aim for at least 4-6 plants per tub.
- Inconsistent watering: Corn is a heavy feeder and incredibly thirsty, especially during tasseling and ear development. Letting it dry out completely or watering erratically will stress the plants, leading to smaller ears and tougher kernels. My experience shows that once temps go above 80F, even 35gal tubs need water twice daily.
- Lack of nutrients: Corn needs a constant supply of nitrogen, phosphorus, and potassium. Relying solely on the initial nutrients in the potting mix isn't enough. Regular liquid feeding (weekly or bi-weekly) is critical for happy, productive plants.
Pro Tips for Maximum Success
Here are a few extra nuggets I've picked up over the seasons that can really boost your corn harvest.- "Hill up" the plants: As corn grows, its roots are relatively shallow. When the plants are about 1-2 feet tall, I like to add a few inches of extra soil or compost around the base of the stalks, creating a small mound. This encourages the development of stronger brace roots, providing better anchorage and nutrient uptake, especially important in a container.
- Succession Planting: If you have multiple tubs, consider planting a new batch of seeds every 2-3 weeks. This won't extend your 90-day cycle for a single ear, but it will give you a continuous harvest of fresh corn over a longer period, rather than all your corn coming ready at once.
- Hand Pollination (for sparse ears): If you notice some silks emerging but no pollen seems to be hitting them, or if your ears are looking sparse, you can gently collect pollen from a mature tassel in a small bag or bowl (do this in the morning when pollen is freshest) and then dust it directly onto the silks of your developing ears. It's a bit tedious, but it can significantly improve ear fill.
- Mulching the Surface: Once your corn plants are established, adding a 1-2 inch layer of organic mulch (like straw, shredded leaves, or wood chips) to the top of the soil in your tubs can make a huge difference. It helps retain moisture, suppresses weeds (though thankfully less of an issue in containers), and keeps the soil temperature more consistent. This is a game-changer for reducing watering frequency.
Keep exploring related guides
Follow the topic cluster below to discover more growing methods, troubleshooting advice, and crop-specific tutorials.