Container Garden Planner

You do not need a yard to grow food. Tomatoes, peppers, herbs, salad greens, strawberries and many other crops grow well in containers on a patio, deck, balcony or front step. This container garden planner helps you plan them. Add each pot by size and choose what to grow in it. The planner checks whether the pot is big enough for that crop, suggests how many plants it holds, and totals the potting mix you need, in cubic feet, dry quarts and bags. Your plan saves automatically in this browser.

How to use the container garden planner

1. Choose a pot size in gallons, from 1 to 25.
2. Choose a crop for that pot.
3. Add the pot. It appears in your list with a plant count, or a warning if the pot is too small.
4. Repeat for every container you plan to plant.
5. Read the totals: number of pots, total volume, potting mix needed, and how many pots are undersized.
6. Remove individual pots, or print the plan to take shopping.

Pot sizes for common crops

Container size is the single biggest factor in container success. A pot that is too small dries out quickly, restricts roots and limits the harvest. These are the minimum sizes the planner uses:

Larger pots hold more plants. A 4-gallon pot of lettuce can hold about twice as many plants as a 2-gallon pot. Larger pots also hold more water, so they need watering less often, which matters a lot in summer heat.

Choosing containers

• Drainage holes are essential. Without them, water collects at the bottom and roots rot. Decorative pots without holes can hold a plastic pot that drains.
• Plastic and glazed pots hold moisture well and are lightweight, good for thirsty crops in hot weather.
• Unglazed terracotta breathes and dries out faster, which suits herbs that dislike wet roots, but needs more frequent watering for vegetables.
• Fabric grow bags drain and breathe well, fold away for winter, and are inexpensive in large sizes, which makes them popular for potatoes and tomatoes.
• Self-watering containers have a water reservoir in the base, which reduces watering frequency and suits busy gardeners.
• Dark containers can get hot in full sun, warming roots. Lighter colors stay cooler.
• Depth matters for roots. Carrots need deep pots, at least 10 inches; lettuce and herbs are happy in shallower, wider containers.

Potting mix: the right soil for containers

Containers need potting mix, not garden soil. Garden soil packs down in pots, drains poorly and can carry diseases. Bagged potting mixes are made from peat or coco coir, bark and perlite, which stay light and airy.

Potting mix is often sold by the dry quart or liter rather than by the cubic foot. One cubic foot is about 25.7 dry quarts, or about 28.3 liters. One cubic foot is also about 7.5 gallons, which is how the planner converts pot sizes into potting mix. Nominal pot sizes often hold somewhat less than their stated volume, so the planner’s estimate tends to be generous.

Many gardeners improve bagged potting mix by blending in some compost, roughly one part compost to two or three parts mix, to add nutrients and help it hold moisture. Because frequent watering washes nutrients out of pots, container crops usually need regular feeding through the season with a slow-release or liquid fertilizer.

Sun and placement

Containers give you one big advantage over beds: you can move them to the sun. Most fruiting vegetables need at least six hours of direct sun, while lettuce and many herbs manage with less. In the Northern Hemisphere, south- and west-facing patios and balconies usually get the most sun. The sunlight requirement finder shows which crops suit the light you have.

Group pots together where you can. They shade each other’s sides, which keeps roots cooler and reduces water loss. On hot balconies, keep pots off reflective surfaces that radiate heat.

Watering containers

Containers dry out much faster than beds, especially small pots in full sun. In midsummer, many need water every day, and small pots or hanging baskets may need it twice.

• Check daily. Push a finger an inch or two into the mix, or lift the pot to feel its weight.
• Water thoroughly until water runs from the drainage holes.
• Empty saucers after watering so roots do not sit in water.
• Mulch the surface with a thin layer of straw, bark or compost to slow evaporation.
• Consider drip irrigation. A simple container drip kit on a timer, with an emitter in each pot, takes care of daily watering. The drip irrigation calculator helps size it.

If plants droop in wet mix, see the overwatering checker; pots without drainage are especially prone to overwatering.

Best crops for containers

• Herbs: basil, parsley, chives, thyme and mint, which is best kept in its own pot so it does not take over.
• Salad greens: lettuce, spinach and arugula in wide, shallow containers, harvested leaf by leaf.
• Peppers and eggplant: compact plants that thrive in the warmth of a container.
• Tomatoes: choose patio, dwarf or determinate varieties for smaller pots, and give indeterminate varieties 10 to 20 gallons and a tall stake.
• Bush beans and peas: productive in medium pots, with a small trellis for peas.
• Strawberries: excellent in pots, hanging baskets and window boxes.
• Potatoes: fun in large grow bags, adding more mix as the plants grow.

Sweet corn and sprawling winter squash are rarely worth growing in containers. The plant finder has a filter for small spaces and containers.

A sample balcony plan

A sunny balcony might hold a 10-gallon pot with one tomato, two 5-gallon pots with a pepper each, a 3-gallon pot of bush beans, two 2-gallon pots of lettuce, and four 1-gallon pots of basil, parsley, chives and thyme. That is ten pots, holding 31 gallons in total, and needs a little over 4 cubic feet of potting mix, about three bags of 1.5 cubic feet.

Container gardening through the seasons

• Spring: start with cool-season crops such as lettuce, spinach, peas and radishes. Containers warm up faster than the ground, so you can often plant a little earlier.
• Summer: switch to heat-loving crops: tomatoes, peppers, eggplant, basil and beans. Water daily in hot weather.
• Fall: replant pots with lettuce, kale, chard and herbs as summer crops finish. Containers can be moved to shelter on frosty nights.
• Winter: bring herbs such as parsley, chives and rosemary to a bright windowsill, or grow microgreens indoors.

Arranging containers

A few layout ideas make the most of a small space:

• Tall at the back: place tomatoes and trellised crops against a wall or railing, with shorter pots in front.
• Grow upward: railing planters, hanging baskets and tiered stands add growing space without taking floor area.
• Keep favorites close: put herbs and salad greens nearest the kitchen door, where they will be used most.
• Leave room to water: make sure you can reach every pot with a watering can or hose.

A note on weight

Containers full of wet potting mix are heavy. A large pot can weigh well over 100 pounds when watered. On balconies and roof decks, check your building’s guidance on load limits, spread heavy pots out rather than grouping them in one corner, and place the largest containers near walls or supports. Lightweight potting mix, plastic or fabric pots, and pot feet that let water drain away all help.

Common container mistakes

• Pots that are too small, which dry out quickly and stunt plants.
• No drainage holes, which leads to waterlogged roots.
• Using garden soil instead of potting mix.
• Forgetting to feed, since nutrients wash out of pots with frequent watering.
• Overcrowding, planting more seedlings per pot than it can support.

Feeding and caring for container crops

Containers hold a limited amount of soil, so plants depend on you for food and water more than plants in the ground. Mix a slow-release fertilizer into the potting mix at planting time, then add a liquid feed every week or two once fruiting crops such as tomatoes and peppers start to flower. Leafy crops need less. Watch for pale leaves, which often signal that the plant needs feeding.

Stake or cage tall crops when you plant them, not after they sprawl. Pinch herbs such as basil regularly to keep them bushy. And check pots daily in summer: a few minutes in the morning catches dry soil, pests and ripe produce before they become problems. The pest identifier helps if something starts eating your plants.

Frequently asked questions