We've reached the point in spring where it's finally safe to start transplanting all your little seedlings and starter plants into their summer homes under the Allentown sun. This is our favorite part of the spring; spending a few hours with your hands in the soil has such a healing effect on us! But, it can also be a little nerve-wracking to think about your plants permanently moving outside. Are they ready? Will they survive the big move?
For the best chance of success, its a good idea to plan for this important part of the season.
Check your frost dates, and check the weather for your area. The forecast for the coming days is important, but it's also a good idea to keep track of the weather in the week before you're ready to transplant. If the days have been quite warm, your soil should be plenty warm enough to plant by last weekend in May. But, if it's been overcast and rainy, your soil may still be quite cold. You can warm the soil faster by laying black plastic or landscape fabric on top of it to soak up the sun.
If you haven't started hardening off your plants yet, get started tomorrow. Set them out for about an hour the first day, and extend their time outside each day until they're spending the whole day outside. Moving seedlings and starter plants straight from the protection of the indoors right out to full exposure to the elements is a huge transition, and it will set back their growth. Give them some time to adjust before putting them in their new homes.
It's also important to note the conditions your plants prefer. Now is the time to transplant warm-season vegetables, like peppers, melons, squashes, pumpkins, and tomatoes. These crops need warmer soil temperatures to thrive after transplanting.
Prepare The Garden Beds
If you haven't already, start preparing your garden beds for transplanting. Loosen and aerate the soil, and add fresh soil if it's needed. If you have raised beds, make sure they're rehydrated before you start transplanting.
At this stage, we recommend checking the soil temperature. Ideally, the soil should be above 60º. The best way to make sure your soil temperatures are high enough is to check every morning before the sun is too high, for 3-4 days in a row, and average the results. Make sure the thermometer is in the soil to a depth of about 4 inches, since that's about how deep most starter pots are.
Start Transplanting When It's Cloudy
A day that's warm and relatively overcast is the perfect day for transplanting. Being planted out into the ground or pots is a stressful transition for plants, and the baking hot sun can make it even harder for them.
Even if you've pre-moistened the soil, its still a good idea to water each plant as you are transplanting. Filling each hole halfway with a slightly diluted root fertilizer gives plants an excellent starting boost for life outside.
Once your plants are firmly in the ground, keep an eye on the forecast and be prepared to cover them if there is any risk of freezing temperatures in your area.
How to Transplant Seedlings
Transplanting seedlings or starter plants is pretty simple, but there are a few tips that can help ensure a smooth transition.
Water your seedlings and starter plants before you start transplanting. Damp soil and roots slide out of pots easier.
Avoid pulling the seedlings out of the pots by their stems. A few gentle squeezes around the outside of a pot will normally loosen the soil enough to slide out the root ball. If that doesn't work, slide a narrow trowel or butter knife around the inside edge of the pot. If there are lots of roots growing through the bottom of the pot, loosen or cut those off first so that they don't catch and tug on the rest of the root system. Then, tip the pot almost upside down, supporting the plant stem and top of the soil with one hand, and gently pull the pot off the plant with your other hand.
If you need to grab some part of the plant to get it out of the pot, aim for leaves. Your plant will grow more leaves, but it only has one stem. If you damage the stem, it may kill the plant.
If your plant is extremely root bound, you may need to cut the pot off to get it out.
If you have multiple seedlings in the same container, gently tease their roots apart so they can be planted separately.
For most plants, dig a hole about as deep as the pot your seedling is in, so it sits at about the same level when planted. Tomatoes are different; you can dig a much deeper hole, and bury tomatoes right up to their lowest set of leaves.
Before placing the plant in its hole, fill it half full with water or a diluted root fertilizer.
Whether you need to pick up a few starter plants to transplant, or supplies, from soil to tools to fertilizer, it's all available at our garden center. Our outdoor nursery area is open for shopping, following social distancing protocols.