Harvesting without killing the plant
Growing an herb garden is incredibly rewarding but you need to know how to harvest herbs without killing the plant. One of the joys of an herb garden is, of course, harvesting those herbs for use in the kitchen or dispensary. For the health of your garden, it’s important to harvest herbs so you don’t damage the plant.
Harvesting herbs without killing the plant
The most important rule when it comes to harvesting herbs and not killing the plant is to not take more than 1/3 of the leaves, stems or plant mass. Taking too much at once can kill the plant. A small, regular harvest is better for the plant than a large picking.
It’s also important not to harvest from a very small or newly established plant. They’re busy putting down roots and getting established. Hold off taking anything until you start to see new growth appearing consistently. Yes, that’s especially hard when the very first round of basil starts to show up after a long winter but hang in there. You – and the plant – will be glad you waited a bit longer before sampling those leaves!
Don’t harvest herbs that look distressed. If you see signs of wilting or drooping, take a pass on harvesting until the plant perks back up. A plant in distress is already struggling to survive – removing leaves can make the job harder.
Discolored leaved or plant parts that look damaged should also be avoided. These are generally signs of either pest pressure, disease or nutritional deficiencies. No matter the cause, it’s best to skip harvesting from those herbs.
Here’s some advice for harvesting specific herbs and not killing the plant
How to harvest thyme without killing the plant
Thyme is vigorous and will make new growth to replace harvested stems. Just snip off a stem at its base with a clean cut. As long as you don’t take more than 1/3 of the plant, it will replace the harvest quickly. Alternatively, you can sheer off the top two inches of the plant – this is useful if you think the plant is about to start flowering.
How to harvest mint without killing the plant
Hahahaha, just try to kill mint. Ok, but seriously, follow the 1/3 rule just to be safe. You can take either a few leaves or cut entire sections of stem. Despite its tendency to spread, mint can actually get leggy and sparse if it’s not cut back occasionally. For that reason, I suggest making your stem cut near the ground. Follow this advice for other members of the mint family, like oregano.
How to harvest basil without killing the plant
The 1/3 rule applies here. But basil is remarkably resilient. I’ve regrown a full, leafy plant from a single leafless stem. Nevertheless, it’s best not to tax the plant with a greedy harvest. Take stems or leaves from the upper sections of the plant, which will also encourage it to make new lower growth and not flower. It’s an annual, so as the summer marches on, it will try hard to set flowers. Regularly harvesting the upper leaves will prolong its life but as summer closes, feel free to harvest as much of the plant as you can since it’s time is nigh.
How to harvest parsley without killing the plant
Just snip off the stems as needed, following the 1/3 rule. Cut curled parsley at the base of a ‘clump’ and cut flat leaf parsley at the bottom of the stem. Parsley is fairly vigorous, so it will regrow cut leaves quickly. Keep in mind that parsley is a biennial, so in its second year, it will try desperately to set flowers. Feel free to harvest as much of the plant as you wish before that happens, since it won’t live out its second season.
How to harvest lavender without killing the plant
You won’t necessarily kill lavender by over-harvesting but you can stunt its growth. The good news is that most people want lavender flowers, not leaves, and you can harvest the long flowery stalks to your heart’s content. Lavender does not regrow if you cut into the actual woody plant structure, so if you do need leaves, take them in very small quantities from the uppermost new growth and be sparing. Learn how to dry lavender.
How to harvest rosemary without killing the plant
Unlike lavender, rosemary will make new growth if you cut into the woody stems. In fact, it will make double shoots to replace what you took. For that reason, it’s hard to kill rosemary simply by harvesting a few springs. Still it’s best to use the 1/3 rule and to be mindful of harvesting from all sides of the plant to encourage symmetrical growth.
How to harvest sage without killing the plant
The 1/3 rule is really important for sage because it grows a little slower than some other herbs. Either remove a few leaves from the entire plant or harvest small stems with clumps of leaves. Cut at the base of the leaf nodes to help the plant make new lower growth.
When in doubt, take as little of the plant as possible. If you plan to use large quantities of herbs, it’s best to grow multiple plants so you can spread out the harvest.
The 1/3 rule doesn’t mean you MUST take an entire third – with oregano, mint and other vigorous growers, 1/3 of the plant can look like this. That’s a lot of leaves!
Harvesting roots without killing the plant
This is harder to do, honestly. As soon as you start disturbing the roots of any plant, you run a serious risk of killing the plant. It’s best to just grow plants for their roots and simply harvest the root by taking the entire plant.
But if you want to preserve the parent plant, you can try harvesting by division. The best way to harvest herb roots is to carefully uncover part of the root ball. Then gently pull or cut away a section of the plant. Take the roots, leave, stems, etc. Immediately rebury the remaining plant and give it a good drink.
You may also be able to dig up the entire plant, remove it from the hole and then divide it into smaller clumps. Keep some of the clumps for harvesting and replant the rest to ensure a continuing crop. Division is a common method of propagating perennials but it needs to be done with care.
Never try to divide a plant in peak growing season or during extremely hot weather. Avoid division if a plant if newly established or showing signs of distress. And keep in mind you can only harvest by division if that plant has a complex root system – that is, multiple root sections. Trying to hack off part of a bulb or tuber or taproot will kill the plant.
Leave the remaining plant alone until you see it begin to make new growth.
These echinacea are beautiful but it’s the roots that have the medicine. Harvest roots without killing the plant using the division method.
Harvesting flowers from herbs
Once most herbs set flowers, the flavor in the leaves and stems becomes unpleasant. But if you’re growing herbs for their flowers or seeds, that’s not an issue! The good news about harvesting flowers is that the 1/3 doesn’t apply here. Take as many flowers as you want. In fact, the more you ‘deadhead’ the flowers, the more the plant will produce in response.
Bear in mind many plants grown for the flowers grow as annuals. Making flowers in order to set seeds is the last stage of their year of life. Their time on this earth is nearly over, so harvest from them as needed.
When perennial herbs flower, it’s usually the end of their growing cycle for the season. You can harvest freely of their flowers since the flowers are not life-sustaining the way the leaves are and other plant parts are.
If you’re letting the herbs flower in order to collect seeds, you’ll need to let the flowers finish setting seeds before you start harvesting.
If you’re growing an herb FOR the flowers, you can harvest them with impunity. Chamomile, for example, will produce more flowers if you are diligent about picking them.
What time of day to harvest herbs
The time of day and year you harvest those parts makes a big difference in the properties of the herb. Generally, it’s best to harvest herbs first thing in the day. The concentration of oils in the leaves and plant parts is highest early in the morning. You won’t harm the plant by harvesting at other times, though.
Some perennial herbs will maintain foliage throughout the year, depending on the local climate. While you can still harvest and enjoy these cold hardy herbs, the flavors won’t be as robust as in the heart of summer. So if you want to dry or preserve herbs or use them for infusions or tinctures, it’s best to harvest them during the active growing season.
Harvest herbs before flowering
Unless you specifically want the flowers, be sure the herb hasn’t set any blooms when you harvest. Once a plant begins putting energy into flowers, the flavor of the leaves changes, and not usually for the better. The good news is the regular, modest harvesting will help keep your herbs from flowering.
Harvest all parts of the herb – but make sure it’s the right part for the job
Consider how you’re using the herb before you harvest. Echinacea flowers are lovely but it’s the root that has medicinal properties, for instance.
Take fennel. It’s feathery leaves have a distinct licorice flavor that makes it a popular culinary herb. And the flowers set strongly flavored seeds that dry well.
If your only goal in growing fennel is to sprinkle a bit on fish, then snip off whatever is convenient. But the leaves will change flavor once the plant has flowered. And the bulb, aka the root, can be harvested, cooked and eaten and offers a completely different flavor. In order to maximize your fennel harvest, you need to know if your priority is a supply of fresh leaves, a big harvest of flowers to dry or the bulb.
Chamomile, which has both an annual (Roman) and perennial (German) variety, produces gorgeous green foliage that smells wonderful. But it’s the flowers that make the tea. So in this case, you’d want it to flower and you’d harvest them to dry. (More about Growing Chamomile and Using Chamomile). Conversely, mint tea is made from dried leaves, and once mint flowers, the leaves can lose the desired flavor.
In short, it’s important to know which part of the herb is going to best fulfill your needs before you start to harvest.
How to harvest herbs safely
Most herbs are surprisingly sturdy and they can withstand regular harvests. But there are some important things to know before you get out the shears.
Check the stems
Are they woody or soft? Herbs like thyme or rosemary have stiff, woody stems and are more like shrubs than plants. When you harvest woody plants, it’s important to place your cuts to the advantage of the plant. For a perennial plant that you want to keep in good shape, take your cutting from either new tip growth or from the base of the plant.
When you take cuttings from the new tips, you encourage the plant to put off new growth in lower sections.
When you cut off an older branch, it won’t re-grow from the cut. For this reason, be mindful about harvesting herbs from old growth. But removing older branches can open up the plant and allow water and sunlight to reach the center sections, so there is a time and place for older growth harvesting.
Rosemary is exceptional among shrubby herbs because it will produce new growth from ‘old wood’. Other shrubby herbs like lavender, however, will not. When in doubt research proper harvesting and pruning techniques for your specific variety of herb.
Note that if you’re growing shrubby herbs as annuals, you can generally harvest from any convenient spot on the plant.
Use sharp shears and make a clean, angled cut. The cutting device should be clean and sterilized and sharp enough to accomplish the cut in a single pass. Dull shears can mash the branch and cause damage below the cut edge.
Harvesting basil and other soft stemmed herbs
You can harvest soft stemmed herbs like basil, mint, oregano, etc by either removing leaves or cutting off a section of stem and leaves. They’ll make new growth rapidly on the remaining plant parts. In fact, it’s necessary to regularly remove leaves from herbs like basil to encourage continual new growth throughout the season.
If you’re removing a section of stem, cut just above the joint of two leaves to encourage vigorous regrowth. Remember that many soft stemmed herbs will happily make new roots, so you can cut a section of stem and leaves, remove the leaves you want and then let the rest of the cutting root. How to regrow basil and how to propagate perennials will show you how to turn those cuttings into plants.