Sprout chamber with orange lid and Heat Pack

Heated seed germination kit

Sprout + Heat Pack

A small chamber that holds heat, moisture, and air around the seed. Built so germination is faster and more even than a paper towel or a heat mat.

$69.99 $74.99 Save $5

Free US shipping · or four payments of $17.50 with Shop Pay

Steady temperatureAdjusts in 1°C steps

Reusable siliconeChamber is dishwasher safe

USB-C powerUses far less power than a mat

Lid color

−1+

USB-C cable is included. A wall adapter is not. An Apple 20W adapter works best.

Five out of five seeds started in half my normal wait time. — Dean, on Sprout by Seed Starter

What is in the box

Sprout silicone germination chamber
Heat Pack (USB-C, 20–35°C)
USB-C cable
Temperature tool and manuals

How it works

Seeds need three things to sprout well. This kit is built around those three things, not around a tray and a guess.

01 — HEAT

Warmth that stays put

Heat Pack holds a set temperature from 20–35°C and only draws power when the chamber needs it. Default is 27°C, which covers most common seeds.

02 — MOISTURE

A closed chamber

Food-grade silicone keeps the pad from drying out the way an open paper towel does. You still check moisture. You do not babysit it all day.

03 — AIR

Room to breathe

Channels in the chamber let oxygen in. That is the part a sealed plastic bag usually gets wrong, and it is a common cause of mold.

Sprout kit on a steel table with plants in the background — Small enough to sit on a bench, in a tent, or on a kitchen counter.

Heat Pack on a wooden table in a grow tent — Heat Pack sits in the chamber and runs from USB-C.

Compared with a heat mat

A heat mat warms a wide area and stays on. This kit warms the seed and then holds the temperature.

	Sprout + Heat Pack	Typical heat mat and bag
Temperature	Sensor-driven, about ±0.5°C	Always on, follows the room
Moisture	Insulated chamber	Dries out or stays too wet
Airflow	Passive channels	Often stagnant
Power while holding	About 0.5 watts	15–25 watts, continuously

Sprout + Heat Pack

Typical heat mat and bag

Temperature

Sensor-driven, about ±0.5°C

Always on, follows the room

Moisture

Insulated chamber

Dries out or stays too wet

Airflow

Passive channels

Often stagnant

Power while holding

About 0.5 watts

15–25 watts, continuously

From people using Sprout

These are real comments left on Sprout. This kit page currently has no reviews of its own, which is why they belong here, next to the product, not in a mixed carousel further down the page.

★★★★★

Thirty years of growing, and starting seeds has always been a challenge. Five out of five seeds started in half my normal wait time.

Dean · Sprout by Seed Starter

★★★★★

The sprout on my seedlings came quickly and was ready for the grow medium in 24 hours. The heat and moisture control is spot on.

Ryan · Sprout by Seed Starter

Questions before you buy

Short answers. The manuals on the site cover the rest.

Do I need a separate heat mat?

No. Heat Pack is the heat source. It sits in the chamber. You do not put a mat under a tray.

Is a power adapter included?

The USB-C cable is included. A wall adapter is not. A quality 20W Apple adapter is the one Root Nerds recommends for consistent power.

What seeds work well with this?

Warm-season crops such as peppers, tomatoes, eggplant, melons, and many herbs. It is also useful for older seed or seed you do not want to waste.

How is this different from a humidity dome?

A plastic dome swings in temperature and often traps stale air. This kit holds warmth on purpose and lets air move through the chamber.