The popular yeast and sugar brew does more harm than good. Sugar in the soil feeds mould, and a fermenting brew can burn roots. The version that works is boiled yeast. Boiling breaks the yeast cells open and releases amino acids, succinic acid and B vitamins. Roots can use them right away, which is exactly what a plant needs after transplanting or a cold night.

TL;DR: Boil 3.5 oz (100 g) of fresh yeast (or 2.5 oz / 70 g dry) with 6 aspirin tablets in 1 quart (1 L) of water for 20 minutes. Cool it and make it up to 2.6 gallons (10 L). Water about 1 quart (1 L) per plant at the root, or spray the leaves. Use it the same day, after transplanting and during cold snaps. No sugar.

The recipe

One recipe. Three ingredients: yeast, aspirin and water.

For 2.6 gallons (10 L) of diluted fertilizer:

3.5 oz (100 g) fresh compressed yeast, or 2.5 oz (70 g) active dry yeast. Standard grocery store baking yeast. Not nutritional yeast.
6 aspirin tablets
1 quart (1 L) water for boiling, plus plain water to make up 2.6 gallons (10 L)

Mix it:

Bring 1 quart (1 L) of water to a boil in a pot.
Crumble in the yeast and add the 6 aspirin tablets. Stir.
Boil for 20 minutes. Boiling breaks the yeast cells open.
Let it cool to room temperature.
Pour it into a watering can and add water to bring the total volume to 2.6 gallons (10 L).
Do not add sugar.

Ready to use.

Shelf life: none. Use the cooled solution the same day you make it. Mix a fresh batch each time.

How to apply

Pour about 1 quart (1 L) of the solution at the base of each plant. You can also spray the leaves with the same solution.

When to use it: right after transplanting, and again when a cold snap stresses the plants. Boiled yeast is a recovery feed for stressed plants, not a regular schedule.

Why yeast works as plant fertilizer

Yeast (Saccharomyces cerevisiae) isn't a fertilizer in the traditional NPK sense. It contains almost no nitrogen, phosphorus, or potassium. What it does contain is B vitamins (B1, B2, B6, B12), amino acids, and natural plant growth hormones including cytokinins and auxins.

Boiling is the key step. Heat breaks the yeast cells open, and amino acids, succinic acid and B vitamins spill into the water. Roots take them up right away. Live yeast works the other way round. In the soil it competes with roots for food and ties up nitrogen for a while.

Plants use this feed to recover from stress. That is why it fits two moments: right after transplanting and during a cold snap.

Is yeast fertilizer safe for all plants?

Yes. Boiled yeast made up to 2.6 gallons (10 L) is safe for all vegetables, herbs, flowers, and fruit. It has no sugar, so it does not feed mould or burn roots.

Works on everything from tomatoes to lettuce to roses. Use it where plants are under stress: fresh transplants and plants after a cold night.

What NOT to do

Don't add sugar and don't let it ferment. Sugar feeds mould in the soil, and a fermenting brew can burn roots.

Don't store it. Use the cooled solution the same day. Mix fresh each time you feed.

Don't use it as a routine feed. Boiled yeast supports stressed plants after transplanting and during cold snaps. It is not an NPK fertilizer, so keep your regular feeding plan.

Don't skip the boiling. Live yeast in the soil ties up nitrogen for a while. Boiling for 20 minutes turns it into a feed roots can use right away.

Best for which plants

Boiled yeast helps stressed plants recover. Every plant benefits, but some show it more visibly than others.

Tomatoes. Feed right after transplanting and after a cold night, while the plant is still growing leaves.
Peppers and eggplant. Same family, same use. They stall in cold weather, so feed them after a cold snap.
Cucumbers and squash. Their roots dislike being disturbed. Feed them right after transplanting.
Strawberries. Apply in spring when growth resumes.
Potatoes. Use it when young shoots are hit by a cold night.
Container herbs and flowers. Feed right after repotting.

When yeast fertilizer doesn't seem to help

If you've been feeding with boiled yeast and plants aren't responding, check two things. First: the cause of the stress. Boiled yeast helps plants recover from transplanting and cold. It does not fix pests, disease or a nutrient shortage. Second: your base feeding. Yeast adds amino acids and vitamins, not nitrogen, phosphorus or potassium, so keep your regular feeding plan.

For a full feeding schedule by growth stage, see our vegetable gardening beginner guide.

FAQ

Does yeast fertilizer really work on plants?

Yes, when you boil it. Boiling breaks the yeast cells open and releases amino acids, succinic acid and B vitamins that roots use right away. Live yeast with sugar is a different story: sugar feeds mould in the soil, and the brew can burn roots. Boiled yeast is a support feed for stressed plants, not a traditional NPK fertilizer.

How often should I use yeast fertilizer?

Use it when plants need support: right after transplanting and during cold snaps. It is not a regular weekly feed.

Is yeast fertilizer safe for tomatoes?

Yes. Water about 1 quart (1 L) per plant right after transplanting and again during a cold snap. Boiled yeast gives the roots amino acids and B vitamins when they need to recover. Keep sugar out of it.

Can I store yeast fertilizer for later?

No. Use the cooled solution the same day. Mix a fresh batch every time you feed.

Is there a gardening app that reminds me when to feed?

Yes. The easyDacha garden planner app schedules feeding tasks by growth stage for every plant in your garden. It tells you when to drench, when to switch feeds, and when to stop before harvest. Download at easydacha.com/download.

Three ingredients, faster recovery

Stressed plants need help at the right moment. Boiled yeast gives roots amino acids right after transplanting and during cold snaps. But every growth stage needs something different, and timing matters.

The easyDacha gardening app builds a feeding schedule tied to each plant's growth stage. Seedling through harvest. Each task tells you what to apply and when. No guessing, no spreadsheets.

Try easyDacha app →. The garden planner app that plans your season in 60 seconds. Cancel anytime.