When and how to prune your plants
It may seem counterintuitive to cut back thriving plants. But as all parents know, you have to do what’s best for them in the long run… Pruning your plants will:
- Increase crop production.
- Encourage more compact growth.
- Reduce risk of plant disease.
For pruning all plants, don’t be hack-handed about it and make sure you:
- Use clean cutting tools. If tools aren't clean, you risk transferring disease to another plant.
- Leave a stub of the stem or branch. Don’t cut one branch cleanly off another.
- Prune no more than 1/3 of the plant. If you take any more than this, you’ll make the plant less productive, not more.
- Regularly remove dying leaves of the lowermost mature branches. Prevent plant disease by removing older bottom leaves as they naturally begin turning yellow or brittle.
- Once the plant bolts (flowers/seeds), replace it with a fresh seedling.
- Don't Forget the Roots! As your plants get bigger, their root systems may start to block water and nutrients from reaching fellow plants. Occasional root trimming will keep all your plants healthy.
Below we break down different pruning techniques for your various plant-types.
Pruning vining and trailing plants (e.g. tomatoes, snow peas, cucumbers, eggplants)
Pruning these plants requires using your thumb and forefinger (instead of cutting tools) to remove the soft tips of young plant stems, to produce two stems instead of one. These plants require pruning to direct and contain their growth.
Start pruning these plants when they have 6 leaves per stem, keeping the following tips in mind:
- Cut at the internode between the 4th and 5th leaf. At each node, a new stem will grow, producing 4 new branches. Once these branches have developed into main structural branches, you can prune again to shape your plant as needed.
- Never cut close to the stem you want to keep. Cutting too close allows pathogens to enter the main stem of the plant.
- Remove suckers (side shoots). Suckers are the growth that appears between the stem and a branch. Remove them to direct your plant’s energy into the strongest fruit-bearing stems.
Pruning lettuces, herbs and leafy greens
These plants can truly run wild if they’re not regularly pruned. Remember to:
- Pinch some leaves once 6–8 pairs of leaves have developed on the plant
- Pinch the stem about 1/4 inch above where the plant is branching.
- Sometimes you will see new leaf growth in the axil of the stem and mature leaf—this is the future branch.
When it comes to flowers, pruning is known as “deadheading”. Once flowers have bloomed, they begin to fade. It’s at this point that you need to deadhead. The good news is that deadheading usually leads to another cycle of blooms. If you don’t deadhead, the flowers will go to seed which will end the flower’s life cycle.
Remember, pruning and harvest is crucial for your plants’ health and growing success. If your plants are ready to harvest check out this guide for how to harvest. If your plants have been growing for 2-3 months it also could be time for a seasonal clean - check out this article for how to reset and clean your Airgarden.