Starting Plants Indoors Then Moving Outdoors

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Getting a headstart on gardening season often involves starting plants indoors then moving them outdoors to finish growing.

Knowing how and when to transfer plants outside can prevent the loss of seedlings and all the money, energy, and time you put into getting them started.

So please read on for the tips and tricks to starting plants indoors in your home or greenhouse and moving them outdoors the correct way so your garden can flourish!

When To Put Plants Outside In Spring?

Timing

Timing is crucial when starting plants inside that you plan to transplant in the spring. Follow guidelines on plant germination days on seed packets, and give your seedlings extra time to toughen up and fill out.

You shouldn’t wait too long to start plants because they won’t be mature enough to safely move them outdoors after the last spring thaw. 

You also don’t want to start seeds too early, so their root systems are struggling against the confines of their tray, stunting growth before the ground is warm enough to plant them outdoors.

Temperature

For spring planting of starter flowers or vegetables, you need to wait until the soil temperatures rise above 40°F for cool-season crops and 60°F for warm-season flowers and vegetables.

These are the minimum temperatures that are safe for planting, but an extra five or ten degrees will ensure quicker growth for both cold and warm-season crops.

Some vegetables, like tomatoes, grow even better when soil temperatures are 75-degrees or above. Knowing your plant’s growing preferences will determine the best time to transplant them outdoors in your region.

Use a soil thermometer to monitor soil temperatures around the last frosts of springtime. Try to check the soil after dark, as this is when the soil will be the coldest.

How To Transfer Plants

Transferring plants outdoors is an exciting time for gardeners ready to beautify their landscaping and fill their pantry with the fruits of their harvest.

There is a right and wrong way to move plants outside, and next up are the things you need to do so the transfer goes off without a hitch. 

What To Do And Consider Before The Transfer

The soil and air temperature are now right for you to move your plants outside, but you must consider other factors that play a role in successful transplanting.

Never grab your trays or pots from your greenhouse or home and directly stick them in your garden.

Plants grown indoors will need time to adjust to the outdoor environment for temperature, humidity, and sunlight exposure. 

If you don’t allow them to transition by following a process called “hardening off,” many of your plants may falter and die.

You also need to be ready if a late-season cold snap occurs, heavy rains are forecast that could drown out your transplants, or an unusual heatwave hits your area.

What You Need

A smart gardener is ready with the supplies necessary to start plants indoors and move them outside to their final home in your garden.

Keep on hand:

  • Shade cloth
  • Warming fabric
  • Tarps
  • Garden stakes tall and short
  • Garden cart

With these supplies, you can easily transplant indoor plants outside and help them get established.

Setting plants into a garden cart is an easy way to move them in groups in, out, and about during the hardening-off phase. You can leave all the plants in the cart and roll it around during the transition instead of handling all the trays and pots individually.

Shade cloth can protect plants from too much sunlight, while a warming fabric can ward off damage from unexpected cold snaps. 

A tarp is a quick cover to protect delicate plants and the soil from heavy downpours that can cause root rot or washouts. The tarp is also handy to create a windbreak, so your plant foliage and dirt don’t dry out from high winds.

Use the long garden stakes to prop the fabric a foot or two above the plants so that it won’t crush them. Use the short stakes to hold the edges down so the cover won’t blow away.

Hardening off then transplanting plants you started indoors is simple when you follow these steps:

Step 1 – Allow time for prep before transplant

The transition from indoor to outdoor will take a week or two, so schedule enough time to do it right. 

Step 2 – Reduce Watering Schedule

As you begin to harden off your plants, also taper off watering so they are getting a dose every third day or so. 

It would be best if you let the plants adjust to normal outdoor garden conditions. Most of us prefer to let rains water our garden plants and only intervene with the hose during stretches of dry weather. 

Reducing watering before transplant will make the transition easier on the plant when you don’t plan to keep up with the same watering schedule you had while the plants were indoors.

Step 3 – Transition Plants To Their New Environment

For the first three days, start bringing your plants outside for a couple of hours each day. Situate the plants in a shady location and protect them from brisk winds.

Try to avoid bringing them out during the hottest part of the day to prevent wilting foliage from excessive heat.

Bring the plants inside again each night.

Step 4 – Further Customize Transition Based On Plant Type

For the next four to seven days, add around an hour to your outdoor schedule to build up to eight or so hours daily. 

Move full-sun plants gradually out into the light, but still, avoid the harsh midday sun.

For shade plants, please leave them in a full or partially shady location for their hours outside.

Continue to bring the plants indoors each night, but that can mean onto a covered porch or into the garage or shed.

TIP: If you see plant leaves get whitish spots, this indicates sunburn, so put the plants back into a shadier location when you take them out next. Droopiness and dark portions on leaves, often toward the tip, indicate damage from temperatures that are too cold.

Step 4 – Allow Plants To Stay Out Overnight

After plants are getting a full day outside, leave them out overnight, as long as temperatures at night stay above 45-50°F.

If you’re unsure how the plants will react to cool nights, drape them with warming fabric overnight and remove the cover immediately in the morning.

After several nights outdoors, your plants are ready for transplant into the ground.

Step 5 – Transplant Into Your Garden

Your plants should be ready for transplant after 7 to 14 days.

The best time to place your plants in the ground is after the heat of the day has passed. A cloudy day is helpful but not necessary.

Once you transplant all your trays or pots, gently water the plants to stimulate new root development in the garden soil.

What To Do After

After you move your plants outside, watch over them carefully for the next two weeks for signs of distress.

Besides watching for damage from overexposure to sunlight or cold, keep an eye on soil moisture and nutrient needs.

A seaweed-based fertilizer will give the plants a healthy boost, and keeping the soil consistently moist will encourage roots to spread while keeping foliage firm. 

After a couple of weeks in the ground, your transplants are hopefully doing fine, and you can start caring for them on the same schedule as all your other landscaping plants.

In Summary

Starting plants indoors is a fantastic way to enjoy longer growing seasons and more abundant flowers, fruits, and vegetables.

Don’t make the mistakes that could cause all your plants to die shortly after transplanting. Take the time to follow the guide above, and don’t rush to move plants outdoors before they are ready.

Now that you have the know-how to start plants indoors and move them outdoors in the best way possible, you can increase your garden’s health, beauty, and overall success!