The Ultimate Guide to Growing Hydroponic Cat Grass7 min read


Does your feline friend crave a little greenery?  Cat grass offers cats a tasty source of fiber, aids in digestion, and can even help with those pesky hairballs.  While you can buy pre-grown cat grass, growing it yourself hydroponically is surprisingly easy, incredibly clean, and ensures a fresh supply whenever your cat gets the munchies.

Hydroponic cat grass means no messy soil, faster growth, and the ability to have lush greens for your cat year-round.  This guide will walk you through everything you need, from choosing seeds to offering those first tender blades to your furry companion.

Let’s get started!


What You’ll Need 

Before we dive into the actual growing process, let’s gather our supplies. Here’s what you’ll need to create a thriving hydroponic cat grass setup:

  • Seeds:  Choose a specific cat grass mix or opt for individual grains like wheat, oats, barley, or rye. Look for high-quality, untreated seeds for the safest option.
  • Growing Medium:  This is what supports your seeds and allows their roots to access the nutrient solution. Popular choices include:
  • Rockwool Cubes: Pre-portioned cubes that make planting easy.
  • Expanded Clay Pebbles (LECA): Reusable, pH-neutral pebbles provide good drainage.
  • Coconut Coir:  A sustainable option, but needs thorough rinsing before use.
  • Container:  You have options!
  • Shallow Trays:  Perfect for larger amounts of cat grass.
  • Repurposed Containers:  Plastic food containers with drainage holes work well.
  • Dedicated Hydroponic Trays:  These often come with lids and built-in features.
  • Nutrients:  Choose a hydroponic fertilizer formulated for leafy greens. Start with a diluted solution for young seedlings.
  • Optional (but helpful):
  • pH Meter: For monitoring the acidity of your nutrient solution.
  • EC Meter:  Measures the concentration of nutrients in your water.
  • Small Water Pump/Airstone: To oxygenate your nutrient solution (not essential for small setups).
  • If you want to check out our friends at Lettuce Grow, that would probably be the best option if you are new and just want to get an easy set up. They have the Farmstand and it is really simple and easy to use system, if you don’t have a system already. Check them out!

Important Note: Even with hydroponics, there’s room for flexibility!  Start with the basics, and you can always add more advanced tools to your cat grass growing arsenal later.


Step-by-Step Guide 

Let’s turn those seeds into a feline-friendly feast! Here’s a detailed guide with options for different hydroponic methods:

    1.Seed Preparation

  • Soaking:  Measure out a ½ cup of cat grass seeds (wheat, oats, barley, or a mix) and place them in a clean bowl.  Cover the seeds with about 2 inches of cool water and let them soak for 12-24 hours.
  • Rinsing:  After soaking, drain the water and rinse the seeds several times with fresh, cool water until it runs clear.

   2. Growing Medium Setup

  • Rockwool/Coconut Coir:
  • Rinse your growing medium thoroughly. Dust and debris can clog tender roots.
  • Rockwool Cubes: If using 1-inch cubes, make a shallow indentation in the top of each cube with a toothpick or similar tool.
  • Gently place 2-3 soaked seeds into each indentation or scatter them over the surface of your growing medium.
  • LECA (Clay Pebbles):
  • Give your LECA a good rinse in a colander until the water runs clear. This removes excess dust.
  • Spread a thin, even layer of soaked seeds over the prepped clay pebbles.

  3. Choose Your Hydroponic Method

  • Passive/Kratky:
  • Find a shallow tray (like a baking dish) and a slightly larger container (like a food storage tub).
  • Place your tray with seeds and growing medium inside the larger container.
  • Prepare your nutrient solution according to the product directions, but start with a half-strength solution for young seedlings.
  • Carefully add the nutrient solution to the outer container until the water level reaches about halfway up the sides of  your growing tray.
  • Circulating:
  • Use a clean food container or dedicated hydroponic tray.
  • Prepare your diluted nutrient solution as above.
  • Install a small submersible water pump or an airstone connected to an air pump to create movement and oxygenate the water.

  4. Light and Warmth:

  • Place your setup in a spot with bright, indirect sunlight. A windowsill facing east or west is often perfect.
  • A consistent temperature between 70-75°F (21-24°C) is ideal for fast germination and healthy growth.


Caring for Your Cat Grass 

With a little attention, your hydroponic cat grass will flourish!  Here are a few key care tips:

  • Watering/Nutrients (Passive Systems):
  • Keep an eye on the water level in your reservoir. As your cat grass grows, it will drink up the solution. Top it up as needed, maintaining that halfway-filled level.
  • About once a week, pour out any old solution, briefly rinse the roots, and refill the reservoir with fresh, diluted nutrient mix.
  • Watering/Nutrients (Circulating Systems):
  • The constant movement helps prevent stagnation.  Top up with diluted nutrients as the level drops.
  • For larger setups, completely change out the nutrient solution every 1-2 weeks.
  • Light:
  • Ensure your cat grass receives several hours of bright, indirect sunlight each day. If it gets leggy or pale, it needs more light.  You can supplement with a grow light if necessary.
  • Rotating:
  • Give your cat grass tray a quarter turn every day or so. This promotes even growth and prevents the grass from leaning too much towards your light source.
  • Harvesting:
  • Once your grass reaches 4-6 inches tall, it’s ready for your feline friend to enjoy! Offer the whole tray, or use scissors to snip off portions.

Important: Fresh is best!  For optimal taste and to prevent mold, most cat grass trays last about a week before it’s time to start a new batch.

 The Farmstand Is Your Self-Watering, Self-Fertilizing Solution for an Easy to Grow Harvest

Troubleshooting and Tips 

Even with the best of care, your cat grass might face a few challenges.  Here’s how to handle common issues:

  • Mold Issues:
  • Prevention: Good air circulation is key! Consider a small fan near your setup, but avoid direct drafts on the seedlings.
  • Treatment: If you spot a bit of fuzz on the surface of your growing medium, a light sprinkling of ground cinnamon (a natural antifungal) can help.  Severe mold requires discarding the batch and starting fresh.
  • Yellowing Grass:
  • Check your nutrients:  Yellowing often indicates a nutrient deficiency. Make sure you’re using a balanced hydroponic fertilizer and the pH of your solution is in the optimal range (usually slightly acidic, around 5.5-6.5).
  • Light Matters: If your grass is getting sufficient nutrients but still yellowing, it might need more light.
  • Wilting:
  • Underwatered?: Ensure the roots are in contact with the nutrient solution. In passive systems, the water level may have dropped too low.
  • Overwatered?: Constantly soggy roots lead to problems. Passive hydroponics work because of air pockets in the growing medium. Ensure good drainage if you’re using a circulating system.
  • Keeping a Continuous Supply:  To always have fresh cat grass on hand, stagger your planting!  Start a new tray every week or so. This way, you’ll have a delicious green treat ready just as the previous batch is past its prime.



By growing cat grass hydroponically, you’re providing your feline friend with a healthy, natural, and easily accessible source of greens.  Not only is it fun to watch the quick growth, but it’s incredibly satisfying to see your cat munching happily on something you grew yourself.

Remember, hydroponics eliminates messy soil, reduces the risk of pests, and allows you to enjoy a bountiful supply of cat grass year-round.  With minimal effort, you can create a little patch of indoor jungle that your cat will adore.

So, why not give it a go? Your cat will thank you!


Additional Notes:

  • Experiment:  Different cats have preferences.  Try growing various grains (wheat, oats, rye) to see what your cat loves best.
  • Get Creative:  Decorate your cat grass containers or create fun multi-level setups if you’re feeling ambitious.
  • Share: If your cat produces more cat grass than they can eat, consider sharing your bounty with other feline friends in your life!


FAQ: Growing Hydroponic Cat Grass 

  • How long does it take for cat grass to grow hydroponically? One of the joys of hydroponics is the speed!  With optimal conditions, your cat grass can be ready to nibble in about a week to ten days.
  • Is hydroponic cat grass safe for my cat? Yes!  Hydroponically grown cat grass is perfectly safe, as long as you use quality seeds and avoid any harsh chemicals in your fertilizer.
  • Can I grow cat grass without special equipment? Absolutely! The passive (Kratky) method is incredibly beginner-friendly. All you need is a tray, growing medium, nutrients, and a sunny spot.
  • How often should I change the water in my hydroponic cat grass setup? In passive systems, a full change once a week is usually sufficient. In circulating systems, a complete change every 1-2 weeks is common.
  • My cat isn’t interested in the cat grass, what can I do? Not all cats go wild for cat grass!  You can try offering smaller amounts, growing different varieties, or placing the cat grass near your cat’s favorite hangout spot.





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