Specializing in indoor gardening and hydroponics growing!

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Growco Indoor Garden Supply has been supplying growers with the best quality organic fertilizers, hydroponics systems, and indoor gardening supplies since we opened our first retail store in 1999! Large Orders

We now have two incredible retail stores in West Michigan, and a dedicated full-time warehouse for our internet customers. We stock all of the items that you'll find on this website at the lowest possible price, and we always ship orders out on same day we receive them or on the next business day! We specialize in complete growroom packages, and we will gladly take the time to help you build the growroom of your dreams! Large orders, pallets of soil- whatever you need for your indoor garden- you've come to the right place, we're here to help!

Mills Nutrients


Featured Products

Unique double ended constructions allows doe maximum optical efficiency and uniformity.
$16.95 - $109.95
B’Cuzz Blossom Builder increases the essential oil production of your plants increasing their size, scent, and flavor when the bloom.
Ozone is great at removing smoke, or strong pet smells. It kills mold and mildew in basements, and can eliminate powdery mildew on plants.
Heavy duty 5 gallon measuring bucket that is perfect for a variety of garden-related tasks.

Newest Additions

This spigot is designed to allow for easy dispensing of your 5 and 10 liter sizes of Mills Nutrients.
$14.25 - $76.50
Botanicare KIND Bloom is a plant nutrient that has the perfect phosphorous-to-potassium ratio. Great for increasing biomass and promoting flower initiation.
$14.25 - $76.50
Botanicare Kind Grow is one of a three-part nutrient system from Bontanicare. Grow is ideal for plants in their vegetative period.
$14.25 - $76.50
Botanicare Kind Base is the part of the 3-part KIND nutrient system. Use KIND Base for plants that are in need of a calcium and nitrogen boost.
Mills Nutrients Ultimate PK is a powerful bloom booster for your plants. Apply it during the last portion of your plants bloom cycle to get a more abundant fruit set with great cell structure and amazing aromas.
$76.50 - $297.50
Mills Nutrients C4 is a unique blend of nutrients, bio-stimulants, carbs, and minerals designed to make your blooms explode! Perfect for any growing medium.
$63.75 - $254.95
Mills Nutrients Start-R is a unique bio-stimulant designed to help your plants develop strong roots fast. You will also notice an improvement in media structure and your plants nutrient uptake.
$16.99 - $76.50
Mills Nutrients Basis A & B is a nutrient combo that is know for giving your garden big yields with very little effort.
Hydrotek King Wing Adjustable DE Reflector is a brand new double-ended reflector that is fully adjustable to help get rid of hot spots and shady edges in your garden!
Save 15%
Organic Nutrients Insect Frass is more than a plant food. It contains beneficial micro-organisms, nutrients and Chitin.
Philips Mastercolor LEC 315 Lamps don't work with normal ballasts and are designed to work with the Sun Systems LEC 315 and LEC 630
The Sun System LEC 630 120 volt comes with 3100 K lamps and gives you 1200 watts worth of HID lighting while only using 630 watts!
The Sun System LEC 315 Light Fixture features the innovative Light Emitting Ceramic technology that when combined with the included 4200 K bulb makes this the perfect solution plants in the vegetative growing stages.
Save 24%
Yield Master 8 Inch Air-Cooled Reflector is the perfect solution for lighting your indoor garden. It provides ideal output with its aluminum interior and features air cooling flanges.
Save 15%
ONA Block Apple Crumble is designed to be small enough to rid small enclosed areas for nasty smells. Perfect for lockers, cars, or even a trash can.
Save 16%
ONA Mist Apple Crumble is an odor eliminator that would great in small areas up to 6,000 sq feet! It doesn't cover up odors, it eliminates them leaving you with fresh smelling air!

We always ship in heavy-duty plain brown boxes, and our 15 years of shipping experience help to insure that you will receive your order intact and undamaged every time! We warehouse all of our products, and pride ourselves in getting your order to you fast!

Our staff has many years of hands-on experience
helping customers build grow rooms, dial in nutrient programs, and make seriously productive gardens. Huge selection, low prices, and fast shipping- Growco wants to be your favorite grow shop! Let us help you learn to grow like a pro!

Private, secure online ordering. No registration needed to order. We strive for your complete satisfaction - we want to be your "go-to" source for performance gardening supplies!

Why shop at 4hydroponics.com?

  • FREE shipping on most orders $250 or more when delivered in lower Continental USA.
    (Sorry, Alaska and Hawaii not included.) Oversized or heavyweight items not included.
  • NO sales tax when delivery is outside of Michigan. In some states that's a 10% savings!
  • VERY competitive pricing.
  • No registration needed to place an order.
  • When we ship your order, magazines or catalogs are liberally included. (More info)
  • Read customer feedback here.

Shipping to Michigan? Expect delivery within 2 business days!


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