Windowsill Herbs and Regrowing Kitchen Scraps: What Really Works

Fresh herbs are one of those grocery items that quietly cost a lot for what you use. You buy a bunch of cilantro for one recipe, use a quarter of it, and the rest wilts in the drawer. Green onions go the same way. Social media, meanwhile, promises endless vegetables from windowsill scraps.

The truth sits in between. A few scraps regrow well and save a purchase or two; others produce very little. A couple of herb pots from seed or cuttings can supply a household for months. Here is what has worked for us and what to skip.

🧅 Which scraps are actually worth regrowing?

Judge each scrap by one question: does it give you something you would otherwise buy, in a reasonable amount of time?

The honest takeaway: green onions and herb cuttings are the clear winners. Celery and lettuce are fine bonuses. Pineapple and avocado are lovely houseplants, not grocery savings.

🌿 How do you regrow green onions?

This is the easiest regrowing project in the kitchen and the one that pays back fastest.

1. Leave about 1 to 2 inches of white bulb with the roots attached when you chop green onions.
2. Stand them roots-down in a small glass or jar with enough water to cover the roots and part of the white, but not the cut top.
3. Set the jar on a bright windowsill.
4. Change the water every day or two. This is the step people skip. Stale water gets cloudy and slimy, and the bulbs rot.
5. Snip the green tops when they are 4 to 6 inches tall, leaving the base to regrow.

In water, you can usually get two or three good harvests before the plants weaken. For more, move the rooted bulbs into a small pot of soil after the first week. In soil they keep producing for much longer.

🥬 What about celery, lettuce and garlic?

Celery base: Cut the stalks about 2 inches above the root end. Set the base in a shallow dish with about half an inch of water, cut side up. Change the water every couple of days. New pale-green leaves and thin stalks appear from the center within about a week. You will not get a full grocery-store head, but the tender leaves and small stalks are great in soups, stocks and stir-fries. If it starts to root well, plant it in soil to keep it going.

Romaine or leaf lettuce: Same method as celery. Expect a small cluster of leaves, enough for a sandwich or a garnish, before the plant tries to flower and turns bitter.

Sprouted garlic: Instead of tossing a clove with a green shoot, push it pointed-end up into a small pot of soil, or stand it in a little water. Snip the green shoots for a mild garlic flavor on eggs, potatoes or noodles.

Grocery potatoes and sweet potatoes: These can grow, but store potatoes are sometimes treated to slow sprouting, and potatoes need a large container or garden bed. If you want to grow potatoes, buy certified seed potatoes from a garden center instead.

🪴 Which herbs are easiest to grow on a windowsill?

For steady supply, herbs grown from seed or rooted cuttings beat scraps. Good picks for indoor windowsills:

• Basil: Root grocery-store basil stems in water (remove the lower leaves first), then pot them. Pinch off the top sets of leaves often to keep it bushy, and pinch flower buds as soon as they show.
• Mint: Extremely easy from cuttings. Keep it in its own pot, because it spreads aggressively.
• Parsley: Slow to start from seed but long-lasting once it gets going.
• Chives: Hardy and forgiving; snip from the outside.
• Oregano and thyme: Grow well from cuttings and prefer drier soil.
• Cilantro: The trickiest indoors; it tends to bolt (go to seed) quickly in warm rooms. Sow a small pot every few weeks for a steady supply.

What herbs need indoors:

• Light. Most culinary herbs want at least 6 hours of direct sun. A south- or west-facing window works best in most US homes. A low-cost LED grow light helps in dim apartments and in winter.
• Drainage. Use pots with drainage holes and a saucer. Soggy roots are the most common cause of dead herbs.
• Potting mix, not garden soil. Bagged potting mix drains well and is less likely to bring in pests.
• Water when the top inch is dry. Stick a finger in the soil to check.

Tip: You don't need to buy fancy planters. Yogurt tubs, clean cans and takeout containers work as pots if you poke drainage holes in the bottom and set them on a plate or tray.

🧼 What food safety basics apply to home-grown greens?

Home-grown is not automatically clean. Soil, water, dust and hands can all carry bacteria. Treat your windowsill harvest like store-bought produce:

• Wash your hands before harvesting and handling.
• Rinse herbs and greens under running water just before using. FoodSafety.gov's four steps to food safety advise rinsing produce without soap, bleach or commercial produce washes.
• Use clean scissors to harvest, and wash the jars you use for regrowing regularly.
• Throw out anything slimy or moldy. If the water in a regrowing jar turns cloudy and smells bad, discard the scrap and start over.

A note on sprouts: Growing alfalfa, mung bean or radish sprouts in a jar is a different project from regrowing scraps. The FDA warns that the warm, humid conditions used to grow sprouts are also ideal for bacteria, and that this can happen even when you grow your own under clean conditions. The FDA advises children, older adults, pregnant women and people with weakened immune systems to avoid raw or lightly cooked sprouts of any kind. Microgreens grown in soil and cut above the soil line are a different and lower-fuss option if you want something in that style.

💵 Does this really save money?

It depends on what you grow and how you use it. Green onions and a few herb pots used in everyday cooking give the most return, because those are items people buy often and waste often. Here is a quick way to judge for your own kitchen:

• Note how often you buy green onions or a particular herb, and how much of each bunch gets thrown away.
• If you buy one every week and toss half, a jar on the windowsill or a single pot can cover much of that need.
• Factor in the one-time cost of potting mix or a seed packet; it is usually covered after a few weeks of not buying that herb.

Regrowing lettuce or pineapple tops is better thought of as a cheap, fun project with kids than a budget strategy.

🏁 Start small, start with green onions

Put the next bunch of green onion roots in a jar of water, change it every day or two, and see how much you get. Add a pot of basil or mint from cuttings, give them a sunny window, and rinse everything before eating. That small setup does more for a grocery budget than a windowsill full of experiments.

❓ Frequently Asked Questions

Why did my green onions get slimy and smell bad?

The water was not changed often enough, or too much of the onion was submerged. Change the water every day or two, keep only the roots and part of the white in water, and rinse the jar each time.

Can I regrow herbs from a grocery-store potted plant?

Yes, and those are often the best deal. Supermarket pots usually hold many seedlings crowded together. Gently divide them into three or four smaller pots with fresh potting mix and they will grow much better.

Do I need a grow light?

Not if you have a window with at least 6 hours of direct sun. In dim apartments or northern winters, a small LED grow light placed a few inches above the plants for 12 to 14 hours a day keeps herbs from turning leggy and pale.

Is it safe to eat regrown vegetables raw?

Yes, if you handle them like any fresh produce: clean hands, clean tools, and a rinse under running water before eating. Discard anything that looks slimy or moldy.