How to Grow Cucumbers in Pots

Getting the Pot Ready

Choose a bush variety of cucumber for containers. In general, bush varieties are easier to grow in pots than vine varieties, which need a trellis to climb and spread out on. Picking a variety suited to a container will give you a higher chance of success. Varieties that are well-suited for container growing include the Salad Bush Hybrid, Bush Champion, Spacemaster, Hybrid Bush Crop, Baby Bush, Bush Pickle, and Potluck.

Select a pot that is 10 in (25 cm) wide for your cucumbers. Your pot should be at least this wide in diameter, as well as that deep, too. If you want to grow more than 1 plant in a single pot, try a container that is at least 20 inches (51 cm) in diameter and holds 5 gallons (19 L). When using a container outdoors, go for a larger container if you can. It will retain moisture more effectively. You can even use a rectangular planter box if you add a trellis for the cucumbers to grow on.

Add holes if your container doesn't have them. While cucumbers love water, standing water can cause root damage. Look for a pot that already has drainage holes, if possible. Just flip it over to see if it has holes in the bottom. If your pot doesn't have drainage holes, use a drill to make holes. Choose a masonry drill bit for soft, unfinished terra cotta or a tile and glass drill bit for glazed surfaces. Pick a ⁄4 to ⁄2 in (6.4 to 12.7 mm) bit. Place painter's tape over the bottom of the pot where you want to drill holes. Painter's tape helps steady the bit. Press the bit lightly into the tape, and turn the drill on at a slow speed. Slowly and steadily apply light pressure to the taped area until the drill goes through the pot. Repeat for at least 1 other hole. If you press too hard or try to drill too fast, you may break the pot.

Clean your pot thoroughly with hot water and soap. Pots can contain bacteria that may cause your plant to rot. If you've used the pot for another plant, it may have hidden insect eggs that will hatch and attack your cucumbers. Scrub it down thoroughly with a rag or dish brush and soapy water. Rinse it out several times to make sure you get all the soap out.

Prepare a stake. Vine cucumbers require a trellis or stake to grow. Even though bush cucumbers do not require staking, they do benefit from it. To make one yourself, start with 3 long stakes or bamboo poles. Gather them together at the top, and tie them together with a cord or even yarn. Spread the bottoms of the stakes out to create the teepee shape. Consider a teepee-style metal staking system, available at most hardware and garden supply stores. A staking system encourages the cucumber to climb along it from the start. Place the stake in the pot with the stakes spread out on the inside. The legs of the stake should touch the bottom of the pot. The stake itself should stand straight without needing additional support. If it's wobbly, adjust the legs so that they're even.

Fill the pot with a well-draining soil mix. If you want to mix your own soil, try mixing 1 part sand with 1 part compost and 1 part peat moss or coco coir. Otherwise, you can choose a pre-mixed potting soil designed for growing vegetables. Pack the mix into the pot, carefully patting it in around the stake. Do not make it too compact, however, since your cucumber plant's roots need loose soil to grow in. Leave approximately 1 inch (2.5 centimeters) of empty space between the surface of the soil and the rim of the pot. Check the stake. Try to wiggle it around in the pot. If it still moves around a lot, pack more potting mix in the pot to stabilize the stake. Find potting soil mixes and the ingredients for potting soil at your local garden store. Do not use garden soil, which may be contaminated by bacteria and pests.

Boost nutrition by mixing a good fertilizer into the soil. Use either a 5-10-5 fertilizer or a 14-14-14 slow release formula. Mix it into the soil in the proportions suggested on the label directions, as fertilizers vary widely by brand and type. Alternatively, use a potting soil that already has fertilizer mixed in. The numbers on a bag of fertilizer indicate how much nitrogen, phosphorus, and potassium the fertilizer contains, respectively. Each element nourishes a different part of the plant. A 5-10-5 fertilizer gives your cucumbers a mild dose that focuses on improved vegetable yield. A 14-14-14 fertilizer, on the other hand, keeps the health of your plant balanced, making it safer to give your cucumbers the slightly higher concentration. Choose an organic fertilizer for an environmentally safe alternative.

Planting Seeds and Seedlings

Sow your seeds once the weather warms up to 70 °F (21 °C). Cucumbers need the soil to reach at least 70 °F (21 °C) in order to grow. In many areas, you can start a crop in July and expect a harvest in September. If you live in a warmer area, you may be able to start earlier. Wait until at least 2 weeks after the last frost. If you're planting inside, you can begin the seeds whenever you want.

Poke a ⁄2 in (1.3 cm) hole into the center of the soil. Make the hole about equal in depth and width. You can create it by using your pinky finger or the rounded end of a pencil. If you have a larger planter, place the holes evenly around the edge of a circular planter or evenly across a rectangular planter, depending on the size and shape.

Plant 5-8 seeds in the hole about ⁄2 in (13 mm) deep. Plant more seeds than necessary so that you guarantee success. Planting this many seeds may mean you need to thin once the plants come up, but you're more likely to end up with as many plants as you want. Cucumber seedlings don't like being taken out of a container or handled. Choosing seedlings with organic containers, such as coco coir or peat, allows you to plant them in the soil, container and all, without handling the seedlings too much. The roots will grow through the organic container.

Cover the hole with more of your soil mix. Loosely drop soil over the seeds. Do not squish the soil into the hole, since doing so may damage the seeds. You can gently pat it down when you're done. If you're using a seedling, fill in the hole around the container, and pat it down from the top.

Use an old water bottle as plastic collar. If it's still cool outside, you can protect your plants by creating collars for each one. Cut the tops and bottoms off of large plastic bottles. Wash them thoroughly with hot soap and water. Place one around each sprouting plant. Press it into the ground so it doesn't blow away. These collars provide warmth and wind protection. They may also protect against some pests.

Water the seeds or seedlings directly after planting them. The soil should be thoroughly and noticeably moist after you water the seeds or seedlings. Do not supersaturate the soil, however, since puddles of water may end up scattering the seeds. Use a fine sprayer so you don't stir up the seeds.

Spread peat moss or straw over the soil after watering. Lightly apply a thin layer of peat moss or mulch over the seeds or seedlings and soil. The mulch helps prevent the soil from drying out too quickly so the seeds and seedlings have a chance to grow.

Place your pot in a bright location with at least 8 hours of sunlight. Cucumbers thrive in warm conditions, and the extra sunlight will keep the soil nice and warm. More than 6 hours of sunlight is even better. If you are growing cucumbers indoors, make sure they are in a sunny room where they get plenty of light. If you don't have a sunny corner, you can buy a grow light instead. Place it above the plant, and keep it on at least 6 hours a day. Placing your pot near the side of your house or by a fence can minimize potential wind damage. A little wind is fine, but strong wind can be damaging.

Caring for Your Cucumbers

Thin your cucumbers out once the seedlings sprout 2 sets of true leaves. Identify the 2 tallest seedlings from each grouping to keep. Snip the other seedlings down to the surface of the soil. Do not yank the other seedlings out, since doing so will disturb the soil and may cause damage to the seedlings you're leaving in the ground. Use garden shears or scissors to snip the extra seedlings off at the soil.

Thin to 1 plant per hole once the plants reach 8 to 10 inches (20 to 25 cm). Examine the plants in each group, and look for the tallest one. It should also have the most leaves and look the healthiest. Snip the other one down to the soil. Now you should have 1 plant growing in each grouping you've made in the pot. In some cases, that may mean you have just a single plant, if you used a small container.

Water your cucumbers daily. If the surface of the soil seems dry, it's time for re-watering. Give mature plants enough water so that a little extra drains out from the drainage holes at the bottom of the pot. Never allow the soil to dry out, since dry soil will inhibit growth and lead to a bitter crop. To check the soil, stick your finger in it. If it's dry, it's time to water. Lift the pot up to see how heavy it is. The heavier the pot, the more saturated the soil is with water. Check the pot throughout the day to get a feeling for how heavy or light the pot gets when you water. Adding mulch around your plant will help it retain more water. If your area is especially dry or hot, you may need to water twice a day.

Add a balanced fertilizer once a week. Drench the soil first before adding the fertilizer. Adding the fertilizer when the plants are dry may create problems. Use a water-soluble fertilizer, and apply as much as the label directs you to use. Fertilizers vary widely by brand and type, so always read the label. Pick a 5-10-5 or 14-14-14 fertilizer.

Eliminate garden pests with neem oil or other organic pesticides. Aphids, pickle worms, mites, and cucumber beetles will all target your cucumber plant. You can make your own organic pesticide with neem oil: To make a spray with neem oil, mix 1 to 1.5 cups (240 to 350 mL) of water with a few drops of dishwashing soap and about 10-20 drops of neem oil. With pests like cucumber beetles, you can simply pick them off by hand using gloves covered in petroleum jelly. Drop them into a bucket of water with a few drops of dishwashing liquid. You can also use a bug vacuum designed for the purpose of sucking insects off plants.

Use an anti-mildew spray on fungal diseases. Mildew and bacterial wilt are especially common. Many anti-fungal products will rid your plants of mildew, but bacterial diseases are more difficult to get rid of. In fact, if your plants develop bacterial wilt, which can be carried by cucumber beetles, the plants will likely die. Fungal infections are often characterized by a white, powdery substance on the leaves. Bacterial wilt starts with the leaves turning dull, wilting in the day, and recovering at night. Eventually, the leaves will turn yellow and die. To make an anti-mildew spray, try mixing 1 tablespoon (14 grams) of baking soda into 1 gallon (3.8 L) of water. Add a dash of dishwashing liquid, and shake it up. Spray it on the plant once a week if you notice a white, powdery mildew on the leaves.

Harvest your cucumbers about 55 days after planting. Bigger cucumbers are more bitter, so harvest cucumbers when they're young. Snip the stem about 1/2-inch (1.27 centimeters) above the cucumber. If the cucumber has reached the yellowing stage, it's probably too mature to eat. Most cucumbers are ready to harvest 55 to 70 days after planting.