A cheap DIY indoor grow setup doesn’t need a grow shop: it needs a closed space, light, airflow and a thermometer. I use a cabinet.

TL;DR

• An old cabinet works as an indoor grow space for vegetables and herbs.
• Light matters most, and it doesn’t have to be expensive.
• A small fan stops mould and trapped heat.
• A thermometer saves you from guessing.
• Start with herbs and leafy greens: they’re the easiest.

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The space: use what you have

My indoor space is an IKEA cabinet, about 50x60x126 cm. I’m not suggesting you buy one: every home has a different gap.

I only ask two things of the space: it closes well, and the light can sit close to the plants. Almost anything works, even a PC case.

Fixing the size first tells you how much light you need, and so how much you’ll spend.

Light: the biggest cost

For vegetables and leafy herbs, light is the main expense. For germination and seedlings, low-wattage grow bulbs are enough.

I started with two Airam PAR30 9.5 W bulbs. They’re weak, with a narrow beam, and only good for seedlings.

For leaves across the whole cabinet I’d move to full-spectrum bulbs. For fruiting tomatoes or chillies you need much more power, and that’s where cheap stops being cheap.

My whole setup cost me 20 €.

Air and temperature

A closed cabinet heats up and holds humidity. A small clip fan moves the air and lowers the risk of mould.

Measure inside, don’t trust your hand. For herbs and leafy greens, about 20 °C by day is a good starting point. More in home temperature for plants.

Automating on a budget

A smart plug that switches the light on and off at the same time every day is already automation. I use Home Assistant, but a plug timer costs less and is enough to start.

For a real example, see hydroponic basil roots.

What to grow first

Start with basil, parsley or lettuce. They forgive more mistakes than tomatoes and give results fast.

Leave fruiting plants until you have the right light.

Where to save and where not to

Save on the furniture, the potting mix and the accessories. Don’t save on measuring: a temperature and humidity sensor costs little and stops you losing plants because you can’t see what’s happening inside.

Don’t buy everything at once either. Build the minimum (space, light, fan), grow for a month and add only what you miss.

If something goes wrong, change one thing at a time. That way you know what fixed it.

Common beginner mistakes

Putting the light too far away: plants stretch looking for it. Overwatering in a closed space: the humidity has nowhere to go and fungus appears.

And closing the cabinet completely with no airflow. Even a little, the fan has to run all the time.

My biggest mistake was not counting on constant airflow. Plants need to breathe, and without air fungus shows up.

FAQ

How much does a cheap DIY indoor grow setup cost? It depends on the light you pick. My whole setup cost me 20 €.

Will any cabinet do? Yes, if it closes well and has room for a light and a fan. Even a PC case.

Can I grow tomatoes in a small cabinet? It’s hard. Weak bulbs won’t set fruit; you need a much stronger light.

Do I need Home Assistant? No. A plug timer is enough to start.