Repurposing Plastic Produce Containers as Mini Greenhouses

Repurposing Plastic Produce Containers as Mini Greenhouses

Home gardeners are always looking for ways to start seedlings early in the growing season before outdoor conditions allow direct sowing of seeds. An easy and affordable solution is repurposing plastic produce containers from the grocery store as mini greenhouses to get a head start on the planting season.

The Benefits of Repurposed Plastic Containers

Clear plastic produce containers have many advantages when used as seed starting greenhouses:

• They are transparent and allow sunlight to pass through to seedlings.
• The clear plastic traps heat inside to keep soil and air warmer than outdoor temperatures.
• The plastic helps retain moisture in the soil so seeds can germinate.
• They have ventilation holes punched in the top allowing some air flow.
• They often have clear lids to keep even more warmth and humidity inside.
• Food-grade plastic is safe for growing edible plants.

Sourcing Free Containers for Repurposing

The best places to find plastic produce containers are grocery stores, food cooperatives, salad bars, and deli counters. Some ideas of what to look for include:

• Lettuce containers
• Berry and tomato cartons
• Packaged salad mix bowls
• Prepared food containers
• Clear clamshell containers

Ask at the service counter if they can set aside clean containers for you instead of tossing them in the recycling. Most grocery stores are happy to oblige, especially for plastic waste reduction and gardening purposes.

Preparing Containers for Growing Seedlings

Before sowing seeds, the plastic produce containers will need some modifications to turn them into effective mini greenhouses:

1. Clean thoroughly with soap and hot water, especially if they held perishables like salad greens or deli foods.
2. Disinfect with a dilute bleach solution to kill any bacteria - 1 part bleach to 9 parts water.
3. Rinse very well and allow to dry fully upside down.
4. Use a hammer and nail to punch 6-8 drainage holes in the bottom of the container.
5. Line the bottom with paper towels, coconut coir, or coffee filters to prevent soil from washing out.
6. Label the outside with the seed variety and sowing date using a permanent marker.

Getting the Best Grow Light Exposure

Even though the repurposed plastic produce containers let in sunlight, seedlings will still need supplemental lighting. The best setup is positioning the mini greenhouses by a sunny window or on a plant rack with grow lights. Ideas include:

• Shelving unit in front of a bright, south-facing window
• Tabletop in a sunroom or solarium
• Light garden rack with full spectrum LED grow lights
• Storage shelves with shop lights hung above

Soil Mix and Sowing Seeds

An appropriate potting mix is key to starting seeds in repurposed plastic produce containers. Aim for a loose, soilless blend like:

• 1 part peat or coconut coir
• 1 part perlite or vermiculite
• 1 part compost

This will provide moisture retention yet stay light and fluffy for tender seedling roots. Fill containers almost to the top with pre-moistened potting mix. Sow seeds according to package directions, usually 1⁄4 inch deep. Cover container with plastic lid or clear plastic wrap to retain humidity. This turns the produce container into a mini greenhouse for germination.

Caring for Seedlings

Tend to seedling care diligently once sprouts emerge from the repurposed plastic produce containers. Follow these tips for robust transplants:

• Light: Ensure 14-16 hours under grow lights or sunlight.
• Air Circulation: Open vents and lids for a few hours daily to refresh oxygen levels.
• Water: Bottom water containers to keep soil moist but not saturated.
• Nutrition: Use 1⁄4 strength all-purpose fertilizer once a week.
• Thinning: Clip extra seedlings with tiny scissors to avoid overcrowding.

Hardening Off Seedlings

Plastic produce containers keep plants protected and tender since conditions stay warm, calm, and humid inside. Seedlings will need a week-long hardening off transition before going outside permanently. To do this:

1. Move plants in containers outside to a shady spot for a few hours daily.
2. Over the course of a week build up to leaving out overnight on mild nights.
3. Open lids and vent holes fully but continue bottom watering daily.
4. The ending goal is to have stocky, slow-growing plants that can withstand wind, sun, and weather shifts outdoors.

Transplanting Tips

Here are some final pointers on moving started seedlings from the repurposed plastic produce containers into garden beds or larger pots when hardening off completes:

• Water seedlings thoroughly the day before so soil releases easily from containers.
• Carefully push plants out from the bottom or gently remove the entire root ball if roots stick through sides.
• Tease apart tangled root balls very gently with fingers or a chopstick.
• Set plant at the same level it grew previously, covering the root ball with native garden soil.
• Water freshly planted areas to remove air pockets and wet soils evenly.

Continue the Gardening Journey with Repurposed Containers

Reusing plastic produce containers as mini greenhouses checks all the boxes for efficiency, value, and sustainability. Home gardeners save money on commercial seed starting options while reducing plastic waste. Turning trash into gardening treasure extends the lifecycle of plastic containers that would otherwise end up in the landfill after one use.

This full circle ethos represents the future of eco-friendly food cultivation. Gardening with repurposed materials aligns with zero waste ambitions and the 3R principles of reducing, reusing, and recycling resources for household needs.

FAQs

What types of plastic produce containers work best?

Opt for clear containers whenever possible to allow in light. Shallow lettuce and berry containers have large surface areas. Avoid darker deli meat tubs or deep rigid containers without ventilation.

Can I reuse plastic drink cups or food tubs?

Yes, clear plastic drink cups and rounded single-serve containers work well too. Thoroughly clean and sanitize anything that held perishable food before repurposing for seed starting though.

How long will seeds last in repurposed containers?

Most seedlings need 6-8 weeks indoors to size up before hardening off and transplanting outdoors. Timeframes vary based on plant variety - quick-growing lettuce takes less time than slower pepper or tomato plants.

What can I do with used plastic planting containers?

Reuse repurposed produce containers year after year for seed starting needs. Containers can also hold garden supplies or become mini greenhouse cloches over transplants outdoors.