The Ins and Outs of Flats of Flowers: Everything You Need To Know

For any gardener or plant lover the term “flat of flowers” is one you’ll come across frequently. But what exactly is a flat of flowers? This handy guide will give you the full lowdown on these popular gardening trays.

An Intro To Flats

In simple terms, a flat is a shallow plastic tray that is used to hold groups of flower pots or plants. Flats make it easier to transport, water, and generally care for multiple plants all at once. They come in different sizes and configurations, but generally have multiple compartments or “cells” to hold the individual pots.

Flats are a gardening must-have because they allow you to grow many seedlings or small plants in one convenient tray. Then, when the plants are ready, the whole flat can be moved in one go. Beats carrying 10 tiny pots around! Flats are commonly used for growing annuals and vegetable seedlings that will later be transplanted into the garden.

Let’s explore the features and uses of these multi-tasking trays…

What To Look For In A Flower Flat

While simple in concept, not all flats are made equal. Here are some things to consider when selecting flats for your garden:

• Size – Flats come in sizes ranging from small 4 or 6 cell trays up to larger 18 or 32 cell configurations. Choose based on the number and size of plants you’ll be growing.

• Material – Most flats are plastic for durability but you can also find biodegradable and compostable options. Make sure the tray is sturdy enough to hold moist soil without sagging.

• Drainage – Key for healthy roots! Look for flats with drainage holes in each cell to allow excess water to escape.

• Growing Cells – Individual cells should be deep enough for roots to develop and have vertical ribs for stability when holding soil and plants.

• Stackable – Flats that can stack together save space. Interlocking stacks also make it easy to move whole groups of flats in one go.

• Reusable – Opt for sturdy flats that can be used for multiple growing seasons rather than flimsier single-use trays. This saves money and reduces waste!

Growing Plants In Flats – From Seeds To Transplant

Flats have two primary uses – starting seeds and helping young plants develop a strong root system before being moved to the garden. Here’s a simple step-by-step for growing with flats:

Starting Seeds:

• Fill each cell 2⁄3 full with moist seed starting mix or potting soil. This allows room for roots to grow downwards.

• Sow seeds into each cell according to package directions, usually 1-2 seeds per cell.

• Lightly cover seeds with soil, tamp down gently, and water soil until moist.

• Cover flat with plastic wrap or dome lid to retain moisture while seeds germinate.

• Once sprouted, remove lid and place flat in sunny spot or under grow lights. Water when soil surface dries out.

• Thin seedlings to one strong plant per cell. Let grow 4-8 weeks until ready to transplant.

Transplanting Seedlings:

• Select young but sturdy plants with 4+ true leaves and developed root systems.

• Water plants well and let soil dry out a bit before transplanting to make removal easier.

• Gently squeeze sides of cell and tip out plant and roots in one piece if possible. Tease apart any circled roots.

• Plant into garden following proper spacing and depth, being careful not to damage roots.

• Water newly planted seedlings well and provide shade until established.

The controlled environment of flats gives seeds the moisture, warmth, and care they need to successfully sprout and grow into young plants ready for the garden.

Creative Uses For Versatile Flats

Beyond starting seeds and transplants, flats have many other creative uses that make them invaluable for gardeners:

• Convenient way to organize and transport smaller nursery plants and pots home from the garden center.

• Hold groups of potted plants that you want to easily move in and out for display.

• Arrange and display companion plants that thrive when grouped together.

• Use as draining drip trays under container plants.

• Start herb cuttings or plant divisions in a cell flat to root before potting up.

• Grow a window sill veggie garden with quick-growing greens and herbs.

• Mix and match flower cuttings in each cell to create unique plant combinations.

• Let cells dry out between watering to please drought tolerant succulents.

Flats are the ultimate multi-tasking, customizable trays for garden, patio, or window sill. The possibilities are endless!

Getting The Most Out Of Your Flower Flats

To help your plants thrive in flats, follow these tips:

• Select trays with good drainage and ventilation. Stagnant moisture invites diseases.

• Use fresh, sterile starting mix and clean flats between uses to avoid mold and pests.

• Place in sunny south-facing window or under grow lights on a 14-16 hour daily cycle.

• Water evenly when top inch of soil dries out. Take care not to overwater or leave standing water.

• Once sprouted, thin plants to prevent overcrowding and competition between seedlings.

• Harden off plants before transplant by setting them outdoors in filtered sun/shade for a week.

• Transplant on a mild, cloudy day and water in well without wetting the leaves.

With proper care, flats provide the ideal environment for plants to develop strong, healthy roots and foliage.

Common Types of Flower Flats

Now that you know the basics, let’s look at some of the most common floral flat sizes and styles:

• 4 or 6 Packs – Smallest size, best for windowsills. Fits 4 or 6 small starter pots.

• 10 or 20 Flats – Popular standard size flat. Has 10-20 individual cells, ideal for most annuals and veggies. Allows close spacing.

• 1801 Flats – Rectangular flats that hold 18 larger starter pots in 3 rows of 6. More room for plants to grow.

• 32 or 36 Cell Flats – Good for smaller plants like Petunias, Marigolds or lettuces which can tolerate close spacing.

• 72 Cell Flats – Mostly used by commercial growers, these have very small compact cells for densely planting clones or plugs.

• Shuttle Trays – A two-tiered stacked flat allowing you to grow microgreens or herbs on top and starter plants below.

• Germination Trays – Come with vented humidity domes to create a greenhouse environment for starting delicate seeds.

• Heavy Duty Flats – Made from thick rigid plastic that supports heavier soils and larger plants. Often have deeper cells.

The range of flat sizes and styles available means you can find the ideal trays tailored to your gardening needs and space.

Get Your Garden Growing!

As you can see, flats are about much more than just starting seeds! With their versatility and ease of use, flower flats are invaluable helpers for growers. This guide covers all the key things to know about successfully using flats indoors and out.

Now that you’re a flat expert, it’s time to put this knowledge to work creating your thriving garden flats! Start seeds, transplant with confidence, and explore creative new ways to use flats this season. Your plants will thank you.